# Primitive Type str

1.0.0 ·
Expand description

String slices.

See also the `std::str` module.

The `str` type, also called a ‘string slice’, is the most primitive string type. It is usually seen in its borrowed form, `&str`. It is also the type of string literals, `&'static str`.

## Basic Usage

String literals are string slices:

    let hello_world = "Hello, World!";

Run

Here we have declared a string slice initialized with a string literal. String literals have a static lifetime, which means the string `hello_world` is guaranteed to be valid for the duration of the entire program. We can explicitly specify `hello_world`’s lifetime as well:

    let hello_world: &'static str = "Hello, world!";

Run

## Representation

A `&str` is made up of two components: a pointer to some bytes, and a length. You can look at these with the `as_ptr` and `len` methods:

    use std::slice;
    use std::str;

    let story = "Once upon a time...";

    let ptr = story.as_ptr();
    let len = story.len();

    // story has nineteen bytes
    assert_eq!(19, len);

    // We can re-build a str out of ptr and len. This is all unsafe because
    // we are responsible for making sure the two components are valid:
    let s = unsafe {
        // First, we build a &[u8]...
        let slice = slice::from_raw_parts(ptr, len);

        // ... and then convert that slice into a string slice
        str::from_utf8(slice)
    };

    assert_eq!(s, Ok(story));

Run

Note: This example shows the internals of `&str`. `unsafe` should not be used to get a string slice under normal circumstances. Use `as_str` instead.

## Invariant

Rust libraries may assume that string slices are always valid UTF-8.

Constructing a non-UTF-8 string slice is not immediate undefined behavior, but any function called on a string slice may assume that it is valid UTF-8, which means that a non-UTF-8 string slice can lead to undefined behavior down the road.

## Implementations§

source§

### impl str

const: 1.39.0 · source

#### pub const fn len(&self) -> usize

Returns the length of `self`.

This length is in bytes, not `char`s or graphemes. In other words, it might not be what a human considers the length of the string.

##### Examples

    let len = "foo".len();
    assert_eq!(3, len);

    assert_eq!("ƒoo".len(), 4); // fancy f!
    assert_eq!("ƒoo".chars().count(), 3);

Run
const: 1.39.0 · source

#### pub const fn is_empty(&self) -> bool

Returns `true` if `self` has a length of zero bytes.

##### Examples

    let s = "";
    assert!(s.is_empty());

    let s = "not empty";
    assert!(!s.is_empty());

Run
1.9.0 · source

#### pub fn is_char_boundary(&self, index: usize) -> bool

Checks that `index`-th byte is the first byte in a UTF-8 code point sequence or the end of the string.

The start and end of the string (when `index == self.len()`) are considered to be boundaries.

Returns `false` if `index` is greater than `self.len()`.

##### Examples

    let s = "Löwe 老虎 Léopard";
    assert!(s.is_char_boundary(0));
    // start of `老`
    assert!(s.is_char_boundary(6));
    assert!(s.is_char_boundary(s.len()));

    // second byte of `ö`
    assert!(!s.is_char_boundary(2));

    // third byte of `老`
    assert!(!s.is_char_boundary(8));

Run
source

#### pub fn floor_char_boundary(&self, index: usize) -> usize

🔬This is a nightly-only experimental API. (`round_char_boundary` #93743)

Finds the closest `x` not exceeding `index` where `is_char_boundary(x)` is `true`.

This method can help you truncate a string so that it’s still valid UTF-8, but doesn’t exceed a given number of bytes. Note that this is done purely at the character level and can still visually split graphemes, even though the underlying characters aren’t split. For example, the emoji 🧑‍🔬 (scientist) could be split so that the string only includes 🧑 (person) instead.

##### Examples

    #![feature(round_char_boundary)]
    let s = "❤️🧡💛💚💙💜";
    assert_eq!(s.len(), 26);
    assert!(!s.is_char_boundary(13));

    let closest = s.floor_char_boundary(13);
    assert_eq!(closest, 10);
    assert_eq!(&s[..closest], "❤️🧡");

Run
source

#### pub fn ceil_char_boundary(&self, index: usize) -> usize

🔬This is a nightly-only experimental API. (`round_char_boundary` #93743)

Finds the closest `x` not below `index` where `is_char_boundary(x)` is `true`.

If `index` is greater than the length of the string, this returns the length of the string.

This method is the natural complement to `floor_char_boundary`. See that method for more details.

##### Examples

    #![feature(round_char_boundary)]
    let s = "❤️🧡💛💚💙💜";
    assert_eq!(s.len(), 26);
    assert!(!s.is_char_boundary(13));

    let closest = s.ceil_char_boundary(13);
    assert_eq!(closest, 14);
    assert_eq!(&s[..closest], "❤️🧡💛");

Run
const: 1.39.0 · source

#### pub const fn as_bytes(&self) -> &[u8] ⓘ

Converts a string slice to a byte slice. To convert the byte slice back into a string slice, use the `from_utf8` function.

##### Examples

    let bytes = "bors".as_bytes();
    assert_eq!(b"bors", bytes);

Run
1.20.0 · source

#### pub unsafe fn as_bytes_mut(&mut self) -> &mut [u8] ⓘ

Converts a mutable string slice to a mutable byte slice.

##### Safety

The caller must ensure that the content of the slice is valid UTF-8 before the borrow ends and the underlying `str` is used.

Use of a `str` whose contents are not valid UTF-8 is undefined behavior.

##### Examples

Basic usage:

    let mut s = String::from("Hello");
    let bytes = unsafe { s.as_bytes_mut() };

    assert_eq!(b"Hello", bytes);

Run

Mutability:

    let mut s = String::from("🗻∈🌏");

    unsafe {
        let bytes = s.as_bytes_mut();

        bytes[0] = 0xF0;
        bytes[1] = 0x9F;
        bytes[2] = 0x8D;
        bytes[3] = 0x94;
    }

    assert_eq!("🍔∈🌏", s);

Run
const: 1.32.0 · source

#### pub const fn as_ptr(&self) -> *const u8

Converts a string slice to a raw pointer.

As string slices are a slice of bytes, the raw pointer points to a `u8`. This pointer will be pointing to the first byte of the string slice.

The caller must ensure that the returned pointer is never written to. If you need to mutate the contents of the string slice, use `as_mut_ptr`.

##### Examples

    let s = "Hello";
    let ptr = s.as_ptr();

Run
1.36.0 · source

#### pub fn as_mut_ptr(&mut self) -> *mut u8

Converts a mutable string slice to a raw pointer.

As string slices are a slice of bytes, the raw pointer points to a `u8`. This pointer will be pointing to the first byte of the string slice.

It is your responsibility to make sure that the string slice only gets modified in a way that it remains valid UTF-8.

1.20.0 · source

#### pub fn get<I>(&self, i: I) -> Option<&<I as SliceIndex<str>>::Output>where I: SliceIndex<str>,

Returns a subslice of `str`.

This is the non-panicking alternative to indexing the `str`. Returns `None` whenever equivalent indexing operation would panic.

##### Examples

    let v = String::from("🗻∈🌏");

    assert_eq!(Some("🗻"), v.get(0..4));

    // indices not on UTF-8 sequence boundaries
    assert!(v.get(1..).is_none());
    assert!(v.get(..8).is_none());

    // out of bounds
    assert!(v.get(..42).is_none());

Run
1.20.0 · source

#### pub fn get_mut<I>( &mut self, i: I ) -> Option<&mut <I as SliceIndex<str>>::Output>where I: SliceIndex<str>,

Returns a mutable subslice of `str`.

This is the non-panicking alternative to indexing the `str`. Returns `None` whenever equivalent indexing operation would panic.

##### Examples

    let mut v = String::from("hello");
    // correct length
    assert!(v.get_mut(0..5).is_some());
    // out of bounds
    assert!(v.get_mut(..42).is_none());
    assert_eq!(Some("he"), v.get_mut(0..2).map(|v| &*v));

    assert_eq!("hello", v);
    {
        let s = v.get_mut(0..2);
        let s = s.map(|s| {
            s.make_ascii_uppercase();
            &*s
        });
        assert_eq!(Some("HE"), s);
    }
    assert_eq!("HEllo", v);

Run
1.20.0 · source

#### pub unsafe fn get_unchecked<I>(&self, i: I) -> &<I as SliceIndex<str>>::Output where I: SliceIndex<str>,

Returns an unchecked subslice of `str`.

This is the unchecked alternative to indexing the `str`.

##### Safety

Callers of this function are responsible that these preconditions are satisfied:

- The starting index must not exceed the ending index;
- Indexes must be within bounds of the original slice;
- Indexes must lie on UTF-8 sequence boundaries.

Failing that, the returned string slice may reference invalid memory or violate the invariants communicated by the `str` type.

##### Examples

    let v = "🗻∈🌏";
    unsafe {
        assert_eq!("🗻", v.get_unchecked(0..4));
        assert_eq!("∈", v.get_unchecked(4..7));
        assert_eq!("🌏", v.get_unchecked(7..11));
    }

Run
1.20.0 · source

#### pub unsafe fn get_unchecked_mut<I>( &mut self, i: I ) -> &mut <I as SliceIndex<str>>::Output where I: SliceIndex<str>,

Returns a mutable, unchecked subslice of `str`.

This is the unchecked alternative to indexing the `str`.

##### Safety

Callers of this function are responsible that these preconditions are satisfied:

- The starting index must not exceed the ending index;
- Indexes must be within bounds of the original slice;
- Indexes must lie on UTF-8 sequence boundaries.

Failing that, the returned string slice may reference invalid memory or violate the invariants communicated by the `str` type.

##### Examples

    let mut v = String::from("🗻∈🌏");
    unsafe {
        assert_eq!("🗻", v.get_unchecked_mut(0..4));
        assert_eq!("∈", v.get_unchecked_mut(4..7));
        assert_eq!("🌏", v.get_unchecked_mut(7..11));
    }

Run
source

#### pub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str

👎Deprecated since 1.29.0: use `get_unchecked(begin..end)` instead

Creates a string slice from another string slice, bypassing safety checks.

This is generally not recommended, use with caution! For a safe alternative see `str` and `Index`.

This new slice goes from `begin` to `end`, including `begin` but excluding `end`.

To get a mutable string slice instead, see the `slice_mut_unchecked` method.

##### Safety

Callers of this function are responsible that three preconditions are satisfied:

- `begin` must not exceed `end`.
- `begin` and `end` must be byte positions within the string slice.
- `begin` and `end` must lie on UTF-8 sequence boundaries.

##### Examples

    let s = "Löwe 老虎 Léopard";

    unsafe {
        assert_eq!("Löwe 老虎 Léopard", s.slice_unchecked(0, 21));
    }

    let s = "Hello, world!";

    unsafe {
        assert_eq!("world", s.slice_unchecked(7, 12));
    }

Run
1.5.0 · source

#### pub unsafe fn slice_mut_unchecked( &mut self, begin: usize, end: usize ) -> &mut str

👎Deprecated since 1.29.0: use `get_unchecked_mut(begin..end)` instead

Creates a string slice from another string slice, bypassing safety checks. This is generally not recommended, use with caution! For a safe alternative see `str` and `IndexMut`.

This new slice goes from `begin` to `end`, including `begin` but excluding `end`.

To get an immutable string slice instead, see the `slice_unchecked` method.

##### Safety

Callers of this function are responsible that three preconditions are satisfied:

- `begin` must not exceed `end`.
- `begin` and `end` must be byte positions within the string slice.
- `begin` and `end` must lie on UTF-8 sequence boundaries.

1.4.0 · source

#### pub fn split_at(&self, mid: usize) -> (&str, &str)

Divide one string slice into two at an index.

The argument, `mid`, should be a byte offset from the start of the string. It must also be on the boundary of a UTF-8 code point.

The two slices returned go from the start of the string slice to `mid`, and from `mid` to the end of the string slice.

To get mutable string slices instead, see the `split_at_mut` method.

##### Panics

Panics if `mid` is not on a UTF-8 code point boundary, or if it is past the end of the last code point of the string slice.

##### Examples

    let s = "Per Martin-Löf";

    let (first, last) = s.split_at(3);

    assert_eq!("Per", first);
    assert_eq!(" Martin-Löf", last);

Run
1.4.0 · source

#### pub fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str)

Divide one mutable string slice into two at an index.

The argument, `mid`, should be a byte offset from the start of the string. It must also be on the boundary of a UTF-8 code point.

The two slices returned go from the start of the string slice to `mid`, and from `mid` to the end of the string slice.

To get immutable string slices instead, see the `split_at` method.

##### Panics

Panics if `mid` is not on a UTF-8 code point boundary, or if it is past the end of the last code point of the string slice.

##### Examples

    let mut s = "Per Martin-Löf".to_string();
    {
        let (first, last) = s.split_at_mut(3);
        first.make_ascii_uppercase();
        assert_eq!("PER", first);
        assert_eq!(" Martin-Löf", last);
    }
    assert_eq!("PER Martin-Löf", s);

Run
source

#### pub fn chars(&self) -> Chars<'_> ⓘ

Returns an iterator over the `char`s of a string slice.

As a string slice consists of valid UTF-8, we can iterate through a string slice by `char`. This method returns such an iterator.

It’s important to remember that `char` represents a Unicode Scalar Value, and might not match your idea of what a ‘character’ is. Iteration over grapheme clusters may be what you actually want. This functionality is not provided by Rust’s standard library, check crates.io instead.

##### Examples

Basic usage:

    let word = "goodbye";

    let count = word.chars().count();
    assert_eq!(7, count);

    let mut chars = word.chars();

    assert_eq!(Some('g'), chars.next());
    assert_eq!(Some('o'), chars.next());
    assert_eq!(Some('o'), chars.next());
    assert_eq!(Some('d'), chars.next());
    assert_eq!(Some('b'), chars.next());
    assert_eq!(Some('y'), chars.next());
    assert_eq!(Some('e'), chars.next());

    assert_eq!(None, chars.next());

Run

Remember, `char`s might not match your intuition about characters:

    let y = "y̆";

    let mut chars = y.chars();

    assert_eq!(Some('y'), chars.next()); // not 'y̆'
    assert_eq!(Some('\u{0306}'), chars.next());

    assert_eq!(None, chars.next());

Run
source

#### pub fn char_indices(&self) -> CharIndices<'_> ⓘ

Returns an iterator over the `char`s of a string slice, and their positions.

As a string slice consists of valid UTF-8, we can iterate through a string slice by `char`. This method returns an iterator of both these `char`s, as well as their byte positions.

The iterator yields tuples. The position is first, the `char` is second.

##### Examples

Basic usage:

    let word = "goodbye";

    let count = word.char_indices().count();
    assert_eq!(7, count);

    let mut char_indices = word.char_indices();

    assert_eq!(Some((0, 'g')), char_indices.next());
    assert_eq!(Some((1, 'o')), char_indices.next());
    assert_eq!(Some((2, 'o')), char_indices.next());
    assert_eq!(Some((3, 'd')), char_indices.next());
    assert_eq!(Some((4, 'b')), char_indices.next());
    assert_eq!(Some((5, 'y')), char_indices.next());
    assert_eq!(Some((6, 'e')), char_indices.next());

    assert_eq!(None, char_indices.next());

Run

Remember, `char`s might not match your intuition about characters:

    let yes = "y̆es";

    let mut char_indices = yes.char_indices();

    assert_eq!(Some((0, 'y')), char_indices.next()); // not (0, 'y̆')
    assert_eq!(Some((1, '\u{0306}')), char_indices.next());

    // note the 3 here - the previous character took up two bytes
    assert_eq!(Some((3, 'e')), char_indices.next());
    assert_eq!(Some((4, 's')), char_indices.next());

    assert_eq!(None, char_indices.next());

Run
source

#### pub fn bytes(&self) -> Bytes<'_> ⓘ

An iterator over the bytes of a string slice.

As a string slice consists of a sequence of bytes, we can iterate through a string slice by byte. This method returns such an iterator.

##### Examples

    let mut bytes = "bors".bytes();

    assert_eq!(Some(b'b'), bytes.next());
    assert_eq!(Some(b'o'), bytes.next());
    assert_eq!(Some(b'r'), bytes.next());
    assert_eq!(Some(b's'), bytes.next());

    assert_eq!(None, bytes.next());

Run
1.1.0 · source

#### pub fn split_whitespace(&self) -> SplitWhitespace<'_> ⓘ

Splits a string slice by whitespace.

The iterator returned will return string slices that are sub-slices of the original string slice, separated by any amount of whitespace.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property `White_Space`. If you only want to split on ASCII whitespace instead, use `split_ascii_whitespace`.

##### Examples

Basic usage:

    let mut iter = "A few words".split_whitespace();

    assert_eq!(Some("A"), iter.next());
    assert_eq!(Some("few"), iter.next());
    assert_eq!(Some("words"), iter.next());

    assert_eq!(None, iter.next());

Run

All kinds of whitespace are considered:

    let mut iter = " Mary   had\ta\u{2009}little  \n\t lamb".split_whitespace();
    assert_eq!(Some("Mary"), iter.next());
    assert_eq!(Some("had"), iter.next());
    assert_eq!(Some("a"), iter.next());
    assert_eq!(Some("little"), iter.next());
    assert_eq!(Some("lamb"), iter.next());

    assert_eq!(None, iter.next());

Run

If the string is empty or all whitespace, the iterator yields no string slices:

    assert_eq!("".split_whitespace().next(), None);
    assert_eq!("   ".split_whitespace().next(), None);

Run
1.34.0 · source

#### pub fn split_ascii_whitespace(&self) -> SplitAsciiWhitespace<'_> ⓘ

Splits a string slice by ASCII whitespace.

The iterator returned will return string slices that are sub-slices of the original string slice, separated by any amount of ASCII whitespace.

To split by Unicode `Whitespace` instead, use `split_whitespace`.

##### Examples

Basic usage:

    let mut iter = "A few words".split_ascii_whitespace();

    assert_eq!(Some("A"), iter.next());
    assert_eq!(Some("few"), iter.next());
    assert_eq!(Some("words"), iter.next());

    assert_eq!(None, iter.next());

Run

All kinds of ASCII whitespace are considered:

    let mut iter = " Mary   had\ta little  \n\t lamb".split_ascii_whitespace();
    assert_eq!(Some("Mary"), iter.next());
    assert_eq!(Some("had"), iter.next());
    assert_eq!(Some("a"), iter.next());
    assert_eq!(Some("little"), iter.next());
    assert_eq!(Some("lamb"), iter.next());

    assert_eq!(None, iter.next());

Run

If the string is empty or all ASCII whitespace, the iterator yields no string slices:

    assert_eq!("".split_ascii_whitespace().next(), None);
    assert_eq!("   ".split_ascii_whitespace().next(), None);

Run
source

#### pub fn lines(&self) -> Lines<'_> ⓘ

An iterator over the lines of a string, as string slices.

Lines are split at line endings that are either newlines (`\n`) or sequences of a carriage return followed by a line feed (`\r\n`).

Line terminators are not included in the lines returned by the iterator.

Note that any carriage return (`\r`) not immediately followed by a line feed (`\n`) does not split a line. These carriage returns are thereby included in the produced lines.

The final line ending is optional. A string that ends with a final line ending will return the same lines as an otherwise identical string without a final line ending.

##### Examples

Basic usage:

    let text = "foo\r\nbar\n\nbaz\r";
    let mut lines = text.lines();

    assert_eq!(Some("foo"), lines.next());
    assert_eq!(Some("bar"), lines.next());
    assert_eq!(Some(""), lines.next());
    // Trailing carriage return is included in the last line
    assert_eq!(Some("baz\r"), lines.next());

    assert_eq!(None, lines.next());

Run

The final line does not require any ending:

    let text = "foo\nbar\n\r\nbaz";
    let mut lines = text.lines();

    assert_eq!(Some("foo"), lines.next());
    assert_eq!(Some("bar"), lines.next());
    assert_eq!(Some(""), lines.next());
    assert_eq!(Some("baz"), lines.next());

    assert_eq!(None, lines.next());

Run
source

#### pub fn lines_any(&self) -> LinesAny<'_> ⓘ

👎Deprecated since 1.4.0: use lines() instead now

An iterator over the lines of a string.

1.8.0 · source

#### pub fn encode_utf16(&self) -> EncodeUtf16<'_> ⓘ

Returns an iterator of `u16` over the string encoded as UTF-16.

##### Examples

    let text = "Zażółć gęślą jaźń";

    let utf8_len = text.len();
    let utf16_len = text.encode_utf16().count();

    assert!(utf16_len <= utf8_len);

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source

#### pub fn contains<'a, P>(&'a self, pat: P) -> bool where P: Pattern<'a>,

Returns `true` if the given pattern matches a sub-slice of this string slice.

Returns `false` if it does not.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

    let bananas = "bananas";

    assert!(bananas.contains("nana"));
    assert!(!bananas.contains("apples"));

Run
source

#### pub fn starts_with<'a, P>(&'a self, pat: P) -> bool where P: Pattern<'a>,

Returns `true` if the given pattern matches a prefix of this string slice.

Returns `false` if it does not.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

    let bananas = "bananas";

    assert!(bananas.starts_with("bana"));
    assert!(!bananas.starts_with("nana"));

Run
source

#### pub fn ends_with<'a, P>(&'a self, pat: P) -> bool where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Returns `true` if the given pattern matches a suffix of this string slice.

Returns `false` if it does not.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

    let bananas = "bananas";

    assert!(bananas.ends_with("anas"));
    assert!(!bananas.ends_with("nana"));

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#### pub fn find<'a, P>(&'a self, pat: P) -> Option<usize>where P: Pattern<'a>,

Returns the byte index of the first character of this string slice that matches the pattern.

Returns `None` if the pattern doesn’t match.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

Simple patterns:

    let s = "Löwe 老虎 Léopard Gepardi";

    assert_eq!(s.find('L'), Some(0));
    assert_eq!(s.find('é'), Some(14));
    assert_eq!(s.find("pard"), Some(17));

Run

More complex patterns using point-free style and closures:

    let s = "Löwe 老虎 Léopard";

    assert_eq!(s.find(char::is_whitespace), Some(5));
    assert_eq!(s.find(char::is_lowercase), Some(1));
    assert_eq!(s.find(|c: char| c.is_whitespace() || c.is_lowercase()), Some(1));
    assert_eq!(s.find(|c: char| (c < 'o') && (c > 'a')), Some(4));

Run

Not finding the pattern:

    let s = "Löwe 老虎 Léopard";
    let x: &[_] = &['1', '2'];

    assert_eq!(s.find(x), None);

Run
source

#### pub fn rfind<'a, P>(&'a self, pat: P) -> Option<usize>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Returns the byte index for the first character of the last match of the pattern in this string slice.

Returns `None` if the pattern doesn’t match.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

Simple patterns:

    let s = "Löwe 老虎 Léopard Gepardi";

    assert_eq!(s.rfind('L'), Some(13));
    assert_eq!(s.rfind('é'), Some(14));
    assert_eq!(s.rfind("pard"), Some(24));

Run

More complex patterns with closures:

    let s = "Löwe 老虎 Léopard";

    assert_eq!(s.rfind(char::is_whitespace), Some(12));
    assert_eq!(s.rfind(char::is_lowercase), Some(20));

Run

Not finding the pattern:

    let s = "Löwe 老虎 Léopard";
    let x: &[_] = &['1', '2'];

    assert_eq!(s.rfind(x), None);

Run
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#### pub fn split<'a, P>(&'a self, pat: P) -> Split<'a, P> ⓘwhere P: Pattern<'a>,

An iterator over substrings of this string slice, separated by characters matched by a pattern.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Iterator behavior

The returned iterator will be a `DoubleEndedIterator` if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., `char`, but not for `&str`.

If the pattern allows a reverse search but its results might differ from a forward search, the `rsplit` method can be used.

##### Examples

Simple patterns:

    let v: Vec<&str> = "Mary had a little lamb".split(' ').collect();
    assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]);

    let v: Vec<&str> = "".split('X').collect();
    assert_eq!(v, [""]);

    let v: Vec<&str> = "lionXXtigerXleopard".split('X').collect();
    assert_eq!(v, ["lion", "", "tiger", "leopard"]);

    let v: Vec<&str> = "lion::tiger::leopard".split("::").collect();
    assert_eq!(v, ["lion", "tiger", "leopard"]);

    let v: Vec<&str> = "abc1def2ghi".split(char::is_numeric).collect();
    assert_eq!(v, ["abc", "def", "ghi"]);

    let v: Vec<&str> = "lionXtigerXleopard".split(char::is_uppercase).collect();
    assert_eq!(v, ["lion", "tiger", "leopard"]);

Run

If the pattern is a slice of chars, split on each occurrence of any of the characters:

    let v: Vec<&str> = "2020-11-03 23:59".split(&['-', ' ', ':', '@'][..]).collect();
    assert_eq!(v, ["2020", "11", "03", "23", "59"]);

Run

A more complex pattern, using a closure:

    let v: Vec<&str> = "abc1defXghi".split(|c| c == '1' || c == 'X').collect();
    assert_eq!(v, ["abc", "def", "ghi"]);

Run

If a string contains multiple contiguous separators, you will end up with empty strings in the output:

    let x = "||||a||b|c".to_string();
    let d: Vec<_> = x.split('|').collect();

    assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);

Run

Contiguous separators are separated by the empty string.

    let x = "(///)".to_string();
    let d: Vec<_> = x.split('/').collect();

    assert_eq!(d, &["(", "", "", ")"]);

Run

Separators at the start or end of a string are neighbored by empty strings.

    let d: Vec<_> = "010".split("0").collect();
    assert_eq!(d, &["", "1", ""]);

Run

When the empty string is used as a separator, it separates every character in the string, along with the beginning and end of the string.

    let f: Vec<_> = "rust".split("").collect();
    assert_eq!(f, &["", "r", "u", "s", "t", ""]);

Run

Contiguous separators can lead to possibly surprising behavior when whitespace is used as the separator. This code is correct:

    let x = "    a  b c".to_string();
    let d: Vec<_> = x.split(' ').collect();

    assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);

Run

It does not give you:

ⓘ

    assert_eq!(d, &["a", "b", "c"]);

Run

Use `split_whitespace` for this behavior.

1.51.0 · source

#### pub fn split_inclusive<'a, P>(&'a self, pat: P) -> SplitInclusive<'a, P> ⓘwhere P: Pattern<'a>,

An iterator over substrings of this string slice, separated by characters matched by a pattern. Differs from the iterator produced by `split` in that `split_inclusive` leaves the matched part as the terminator of the substring.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

    let v: Vec<&str> = "Mary had a little lamb\nlittle lamb\nlittle lamb."
        .split_inclusive('\n').collect();
    assert_eq!(v, ["Mary had a little lamb\n", "little lamb\n", "little lamb."]);

Run

If the last element of the string is matched, that element will be considered the terminator of the preceding substring. That substring will be the last item returned by the iterator.

    let v: Vec<&str> = "Mary had a little lamb\nlittle lamb\nlittle lamb.\n"
        .split_inclusive('\n').collect();
    assert_eq!(v, ["Mary had a little lamb\n", "little lamb\n", "little lamb.\n"]);

Run
source

#### pub fn rsplit<'a, P>(&'a self, pat: P) -> RSplit<'a, P> ⓘwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

An iterator over substrings of the given string slice, separated by characters matched by a pattern and yielded in reverse order.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Iterator behavior

The returned iterator requires that the pattern supports a reverse search, and it will be a `DoubleEndedIterator` if a forward/reverse search yields the same elements.

For iterating from the front, the `split` method can be used.

##### Examples

Simple patterns:

    let v: Vec<&str> = "Mary had a little lamb".rsplit(' ').collect();
    assert_eq!(v, ["lamb", "little", "a", "had", "Mary"]);

    let v: Vec<&str> = "".rsplit('X').collect();
    assert_eq!(v, [""]);

    let v: Vec<&str> = "lionXXtigerXleopard".rsplit('X').collect();
    assert_eq!(v, ["leopard", "tiger", "", "lion"]);

    let v: Vec<&str> = "lion::tiger::leopard".rsplit("::").collect();
    assert_eq!(v, ["leopard", "tiger", "lion"]);

Run

A more complex pattern, using a closure:

    let v: Vec<&str> = "abc1defXghi".rsplit(|c| c == '1' || c == 'X').collect();
    assert_eq!(v, ["ghi", "def", "abc"]);

Run
source

#### pub fn split_terminator<'a, P>(&'a self, pat: P) -> SplitTerminator<'a, P> ⓘwhere P: Pattern<'a>,

An iterator over substrings of the given string slice, separated by characters matched by a pattern.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

Equivalent to `split`, except that the trailing substring is skipped if empty.

This method can be used for string data that is terminated, rather than separated by a pattern.

##### Iterator behavior

The returned iterator will be a `DoubleEndedIterator` if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., `char`, but not for `&str`.

If the pattern allows a reverse search but its results might differ from a forward search, the `rsplit_terminator` method can be used.

##### Examples

    let v: Vec<&str> = "A.B.".split_terminator('.').collect();
    assert_eq!(v, ["A", "B"]);

    let v: Vec<&str> = "A..B..".split_terminator(".").collect();
    assert_eq!(v, ["A", "", "B", ""]);

    let v: Vec<&str> = "A.B:C.D".split_terminator(&['.', ':'][..]).collect();
    assert_eq!(v, ["A", "B", "C", "D"]);

Run
source

#### pub fn rsplit_terminator<'a, P>(&'a self, pat: P) -> RSplitTerminator<'a, P> ⓘwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

An iterator over substrings of `self`, separated by characters matched by a pattern and yielded in reverse order.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

Equivalent to `split`, except that the trailing substring is skipped if empty.

This method can be used for string data that is terminated, rather than separated by a pattern.

##### Iterator behavior

The returned iterator requires that the pattern supports a reverse search, and it will be double ended if a forward/reverse search yields the same elements.

For iterating from the front, the `split_terminator` method can be used.

##### Examples

    let v: Vec<&str> = "A.B.".rsplit_terminator('.').collect();
    assert_eq!(v, ["B", "A"]);

    let v: Vec<&str> = "A..B..".rsplit_terminator(".").collect();
    assert_eq!(v, ["", "B", "", "A"]);

    let v: Vec<&str> = "A.B:C.D".rsplit_terminator(&['.', ':'][..]).collect();
    assert_eq!(v, ["D", "C", "B", "A"]);

Run
source

#### pub fn splitn<'a, P>(&'a self, n: usize, pat: P) -> SplitN<'a, P> ⓘwhere P: Pattern<'a>,

An iterator over substrings of the given string slice, separated by a pattern, restricted to returning at most `n` items.

If `n` substrings are returned, the last substring (the `n`th substring) will contain the remainder of the string.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Iterator behavior

The returned iterator will not be double ended, because it is not efficient to support.

If the pattern allows a reverse search, the `rsplitn` method can be used.

##### Examples

Simple patterns:

    let v: Vec<&str> = "Mary had a little lambda".splitn(3, ' ').collect();
    assert_eq!(v, ["Mary", "had", "a little lambda"]);

    let v: Vec<&str> = "lionXXtigerXleopard".splitn(3, "X").collect();
    assert_eq!(v, ["lion", "", "tigerXleopard"]);

    let v: Vec<&str> = "abcXdef".splitn(1, 'X').collect();
    assert_eq!(v, ["abcXdef"]);

    let v: Vec<&str> = "".splitn(1, 'X').collect();
    assert_eq!(v, [""]);

Run

A more complex pattern, using a closure:

    let v: Vec<&str> = "abc1defXghi".splitn(2, |c| c == '1' || c == 'X').collect();
    assert_eq!(v, ["abc", "defXghi"]);

Run
source

#### pub fn rsplitn<'a, P>(&'a self, n: usize, pat: P) -> RSplitN<'a, P> ⓘwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

An iterator over substrings of this string slice, separated by a pattern, starting from the end of the string, restricted to returning at most `n` items.

If `n` substrings are returned, the last substring (the `n`th substring) will contain the remainder of the string.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Iterator behavior

The returned iterator will not be double ended, because it is not efficient to support.

For splitting from the front, the `splitn` method can be used.

##### Examples

Simple patterns:

    let v: Vec<&str> = "Mary had a little lamb".rsplitn(3, ' ').collect();
    assert_eq!(v, ["lamb", "little", "Mary had a"]);

    let v: Vec<&str> = "lionXXtigerXleopard".rsplitn(3, 'X').collect();
    assert_eq!(v, ["leopard", "tiger", "lionX"]);

    let v: Vec<&str> = "lion::tiger::leopard".rsplitn(2, "::").collect();
    assert_eq!(v, ["leopard", "lion::tiger"]);

Run

A more complex pattern, using a closure:

    let v: Vec<&str> = "abc1defXghi".rsplitn(2, |c| c == '1' || c == 'X').collect();
    assert_eq!(v, ["ghi", "abc1def"]);

Run
1.52.0 · source

#### pub fn split_once<'a, P>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)>where P: Pattern<'a>,

Splits the string on the first occurrence of the specified delimiter and returns prefix before delimiter and suffix after delimiter.

##### Examples

    assert_eq!("cfg".split_once('='), None);
    assert_eq!("cfg=".split_once('='), Some(("cfg", "")));
    assert_eq!("cfg=foo".split_once('='), Some(("cfg", "foo")));
    assert_eq!("cfg=foo=bar".split_once('='), Some(("cfg", "foo=bar")));

Run
1.52.0 · source

#### pub fn rsplit_once<'a, P>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Splits the string on the last occurrence of the specified delimiter and returns prefix before delimiter and suffix after delimiter.

##### Examples

    assert_eq!("cfg".rsplit_once('='), None);
    assert_eq!("cfg=foo".rsplit_once('='), Some(("cfg", "foo")));
    assert_eq!("cfg=foo=bar".rsplit_once('='), Some(("cfg=foo", "bar")));

Run
1.2.0 · source

#### pub fn matches<'a, P>(&'a self, pat: P) -> Matches<'a, P> ⓘwhere P: Pattern<'a>,

An iterator over the disjoint matches of a pattern within the given string slice.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Iterator behavior

The returned iterator will be a `DoubleEndedIterator` if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., `char`, but not for `&str`.

If the pattern allows a reverse search but its results might differ from a forward search, the `rmatches` method can be used.

##### Examples

    let v: Vec<&str> = "abcXXXabcYYYabc".matches("abc").collect();
    assert_eq!(v, ["abc", "abc", "abc"]);

    let v: Vec<&str> = "1abc2abc3".matches(char::is_numeric).collect();
    assert_eq!(v, ["1", "2", "3"]);

Run
1.2.0 · source

#### pub fn rmatches<'a, P>(&'a self, pat: P) -> RMatches<'a, P> ⓘwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

An iterator over the disjoint matches of a pattern within this string slice, yielded in reverse order.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Iterator behavior

The returned iterator requires that the pattern supports a reverse search, and it will be a `DoubleEndedIterator` if a forward/reverse search yields the same elements.

For iterating from the front, the `matches` method can be used.

##### Examples

    let v: Vec<&str> = "abcXXXabcYYYabc".rmatches("abc").collect();
    assert_eq!(v, ["abc", "abc", "abc"]);

    let v: Vec<&str> = "1abc2abc3".rmatches(char::is_numeric).collect();
    assert_eq!(v, ["3", "2", "1"]);

Run
1.5.0 · source

#### pub fn match_indices<'a, P>(&'a self, pat: P) -> MatchIndices<'a, P> ⓘwhere P: Pattern<'a>,

An iterator over the disjoint matches of a pattern within this string slice as well as the index that the match starts at.

For matches of `pat` within `self` that overlap, only the indices corresponding to the first match are returned.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Iterator behavior

The returned iterator will be a `DoubleEndedIterator` if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., `char`, but not for `&str`.

If the pattern allows a reverse search but its results might differ from a forward search, the `rmatch_indices` method can be used.

##### Examples

    let v: Vec<_> = "abcXXXabcYYYabc".match_indices("abc").collect();
    assert_eq!(v, [(0, "abc"), (6, "abc"), (12, "abc")]);

    let v: Vec<_> = "1abcabc2".match_indices("abc").collect();
    assert_eq!(v, [(1, "abc"), (4, "abc")]);

    let v: Vec<_> = "ababa".match_indices("aba").collect();
    assert_eq!(v, [(0, "aba")]); // only the first `aba`

Run
1.5.0 · source

#### pub fn rmatch_indices<'a, P>(&'a self, pat: P) -> RMatchIndices<'a, P> ⓘwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

An iterator over the disjoint matches of a pattern within `self`, yielded in reverse order along with the index of the match.

For matches of `pat` within `self` that overlap, only the indices corresponding to the last match are returned.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Iterator behavior

The returned iterator requires that the pattern supports a reverse search, and it will be a `DoubleEndedIterator` if a forward/reverse search yields the same elements.

For iterating from the front, the `match_indices` method can be used.

##### Examples

    let v: Vec<_> = "abcXXXabcYYYabc".rmatch_indices("abc").collect();
    assert_eq!(v, [(12, "abc"), (6, "abc"), (0, "abc")]);

    let v: Vec<_> = "1abcabc2".rmatch_indices("abc").collect();
    assert_eq!(v, [(4, "abc"), (1, "abc")]);

    let v: Vec<_> = "ababa".rmatch_indices("aba").collect();
    assert_eq!(v, [(2, "aba")]); // only the last `aba`

Run
source

#### pub fn trim(&self) -> &str

Returns a string slice with leading and trailing whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property `White_Space`, which includes newlines.

##### Examples

    let s = "\n Hello\tworld\t\n";

    assert_eq!("Hello\tworld", s.trim());

Run
1.30.0 · source

#### pub fn trim_start(&self) -> &str

Returns a string slice with leading whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property `White_Space`, which includes newlines.

##### Text directionality

A string is a sequence of bytes. `start` in this context means the first position of that byte string; for a left-to-right language like English or Russian, this will be left side, and for right-to-left languages like Arabic or Hebrew, this will be the right side.

##### Examples

Basic usage:

    let s = "\n Hello\tworld\t\n";
    assert_eq!("Hello\tworld\t\n", s.trim_start());

Run

Directionality:

    let s = "  English  ";
    assert!(Some('E') == s.trim_start().chars().next());

    let s = "  עברית  ";
    assert!(Some('ע') == s.trim_start().chars().next());

Run
1.30.0 · source

#### pub fn trim_end(&self) -> &str

Returns a string slice with trailing whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property `White_Space`, which includes newlines.

##### Text directionality

A string is a sequence of bytes. `end` in this context means the last position of that byte string; for a left-to-right language like English or Russian, this will be right side, and for right-to-left languages like Arabic or Hebrew, this will be the left side.

##### Examples

Basic usage:

    let s = "\n Hello\tworld\t\n";
    assert_eq!("\n Hello\tworld", s.trim_end());

Run

Directionality:

    let s = "  English  ";
    assert!(Some('h') == s.trim_end().chars().rev().next());

    let s = "  עברית  ";
    assert!(Some('ת') == s.trim_end().chars().rev().next());

Run
source

#### pub fn trim_left(&self) -> &str

👎Deprecated since 1.33.0: superseded by `trim_start`

Returns a string slice with leading whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property `White_Space`.

##### Text directionality

A string is a sequence of bytes. ‘Left’ in this context means the first position of that byte string; for a language like Arabic or Hebrew which are ‘right to left’ rather than ‘left to right’, this will be the right side, not the left.

##### Examples

Basic usage:

    let s = " Hello\tworld\t";

    assert_eq!("Hello\tworld\t", s.trim_left());

Run

Directionality:

    let s = "  English";
    assert!(Some('E') == s.trim_left().chars().next());

    let s = "  עברית";
    assert!(Some('ע') == s.trim_left().chars().next());

Run
source

#### pub fn trim_right(&self) -> &str

👎Deprecated since 1.33.0: superseded by `trim_end`

Returns a string slice with trailing whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property `White_Space`.

##### Text directionality

A string is a sequence of bytes. ‘Right’ in this context means the last position of that byte string; for a language like Arabic or Hebrew which are ‘right to left’ rather than ‘left to right’, this will be the left side, not the right.

##### Examples

Basic usage:

    let s = " Hello\tworld\t";

    assert_eq!(" Hello\tworld", s.trim_right());

Run

Directionality:

    let s = "English  ";
    assert!(Some('h') == s.trim_right().chars().rev().next());

    let s = "עברית  ";
    assert!(Some('ת') == s.trim_right().chars().rev().next());

Run
source

#### pub fn trim_matches<'a, P>(&'a self, pat: P) -> &'a str where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: DoubleEndedSearcher<'a>,

Returns a string slice with all prefixes and suffixes that match a pattern repeatedly removed.

The pattern can be a `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

Simple patterns:

    assert_eq!("11foo1bar11".trim_matches('1'), "foo1bar");
    assert_eq!("123foo1bar123".trim_matches(char::is_numeric), "foo1bar");

    let x: &[_] = &['1', '2'];
    assert_eq!("12foo1bar12".trim_matches(x), "foo1bar");

Run

A more complex pattern, using a closure:

    assert_eq!("1foo1barXX".trim_matches(|c| c == '1' || c == 'X'), "foo1bar");

Run
1.30.0 · source

#### pub fn trim_start_matches<'a, P>(&'a self, pat: P) -> &'a str where P: Pattern<'a>,

Returns a string slice with all prefixes that match a pattern repeatedly removed.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Text directionality

A string is a sequence of bytes. `start` in this context means the first position of that byte string; for a left-to-right language like English or Russian, this will be left side, and for right-to-left languages like Arabic or Hebrew, this will be the right side.

##### Examples

    assert_eq!("11foo1bar11".trim_start_matches('1'), "foo1bar11");
    assert_eq!("123foo1bar123".trim_start_matches(char::is_numeric), "foo1bar123");

    let x: &[_] = &['1', '2'];
    assert_eq!("12foo1bar12".trim_start_matches(x), "foo1bar12");

Run
1.45.0 · source

#### pub fn strip_prefix<'a, P>(&'a self, prefix: P) -> Option<&'a str>where P: Pattern<'a>,

Returns a string slice with the prefix removed.

If the string starts with the pattern `prefix`, returns substring after the prefix, wrapped in `Some`. Unlike `trim_start_matches`, this method removes the prefix exactly once.

If the string does not start with `prefix`, returns `None`.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

    assert_eq!("foo:bar".strip_prefix("foo:"), Some("bar"));
    assert_eq!("foo:bar".strip_prefix("bar"), None);
    assert_eq!("foofoo".strip_prefix("foo"), Some("foo"));

Run
1.45.0 · source

#### pub fn strip_suffix<'a, P>(&'a self, suffix: P) -> Option<&'a str>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Returns a string slice with the suffix removed.

If the string ends with the pattern `suffix`, returns the substring before the suffix, wrapped in `Some`. Unlike `trim_end_matches`, this method removes the suffix exactly once.

If the string does not end with `suffix`, returns `None`.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Examples

    assert_eq!("bar:foo".strip_suffix(":foo"), Some("bar"));
    assert_eq!("bar:foo".strip_suffix("bar"), None);
    assert_eq!("foofoo".strip_suffix("foo"), Some("foo"));

Run
1.30.0 · source

#### pub fn trim_end_matches<'a, P>(&'a self, pat: P) -> &'a str where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Returns a string slice with all suffixes that match a pattern repeatedly removed.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Text directionality

A string is a sequence of bytes. `end` in this context means the last position of that byte string; for a left-to-right language like English or Russian, this will be right side, and for right-to-left languages like Arabic or Hebrew, this will be the left side.

##### Examples

Simple patterns:

    assert_eq!("11foo1bar11".trim_end_matches('1'), "11foo1bar");
    assert_eq!("123foo1bar123".trim_end_matches(char::is_numeric), "123foo1bar");

    let x: &[_] = &['1', '2'];
    assert_eq!("12foo1bar12".trim_end_matches(x), "12foo1bar");

Run

A more complex pattern, using a closure:

    assert_eq!("1fooX".trim_end_matches(|c| c == '1' || c == 'X'), "1foo");

Run
source

#### pub fn trim_left_matches<'a, P>(&'a self, pat: P) -> &'a str where P: Pattern<'a>,

👎Deprecated since 1.33.0: superseded by `trim_start_matches`

Returns a string slice with all prefixes that match a pattern repeatedly removed.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Text directionality

A string is a sequence of bytes. ‘Left’ in this context means the first position of that byte string; for a language like Arabic or Hebrew which are ‘right to left’ rather than ‘left to right’, this will be the right side, not the left.

##### Examples

    assert_eq!("11foo1bar11".trim_left_matches('1'), "foo1bar11");
    assert_eq!("123foo1bar123".trim_left_matches(char::is_numeric), "foo1bar123");

    let x: &[_] = &['1', '2'];
    assert_eq!("12foo1bar12".trim_left_matches(x), "foo1bar12");

Run
source

#### pub fn trim_right_matches<'a, P>(&'a self, pat: P) -> &'a str where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

👎Deprecated since 1.33.0: superseded by `trim_end_matches`

Returns a string slice with all suffixes that match a pattern repeatedly removed.

The pattern can be a `&str`, `char`, a slice of `char`s, or a function or closure that determines if a character matches.

##### Text directionality

A string is a sequence of bytes. ‘Right’ in this context means the last position of that byte string; for a language like Arabic or Hebrew which are ‘right to left’ rather than ‘left to right’, this will be the left side, not the right.

##### Examples

Simple patterns:

    assert_eq!("11foo1bar11".trim_right_matches('1'), "11foo1bar");
    assert_eq!("123foo1bar123".trim_right_matches(char::is_numeric), "123foo1bar");

    let x: &[_] = &['1', '2'];
    assert_eq!("12foo1bar12".trim_right_matches(x), "12foo1bar");

Run

A more complex pattern, using a closure:

    assert_eq!("1fooX".trim_right_matches(|c| c == '1' || c == 'X'), "1foo");

Run
source

#### pub fn parse<F>(&self) -> Result<F, <F as FromStr>::Err>where F: FromStr,

Parses this string slice into another type.

Because `parse` is so general, it can cause problems with type inference. As such, `parse` is one of the few times you’ll see the syntax affectionately known as the ‘turbofish’: `::<>`. This helps the inference algorithm understand specifically which type you’re trying to parse into.

`parse` can parse into any type that implements the `FromStr` trait.

##### Errors

Will return `Err` if it’s not possible to parse this string slice into the desired type.

##### Examples

Basic usage

    let four: u32 = "4".parse().unwrap();

    assert_eq!(4, four);

Run

Using the ‘turbofish’ instead of annotating `four`:

    let four = "4".parse::<u32>();

    assert_eq!(Ok(4), four);

Run

Failing to parse:

    let nope = "j".parse::<u32>();

    assert!(nope.is_err());

Run
1.23.0 (const: 1.74.0) · source

#### pub const fn is_ascii(&self) -> bool

Checks if all characters in this string are within the ASCII range.

##### Examples

    let ascii = "hello!\n";
    let non_ascii = "Grüße, Jürgen ❤";

    assert!(ascii.is_ascii());
    assert!(!non_ascii.is_ascii());

Run
source

#### pub const fn as_ascii(&self) -> Option<&[AsciiChar]>

🔬This is a nightly-only experimental API. (`ascii_char` #110998)

If this string slice `is_ascii`, returns it as a slice of ASCII characters, otherwise returns `None`.

1.23.0 · source

#### pub fn eq_ignore_ascii_case(&self, other: &str) -> bool

Checks that two strings are an ASCII case-insensitive match.

Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`, but without allocating and copying temporaries.

##### Examples

    assert!("Ferris".eq_ignore_ascii_case("FERRIS"));
    assert!("Ferrös".eq_ignore_ascii_case("FERRöS"));
    assert!(!"Ferrös".eq_ignore_ascii_case("FERRÖS"));

Run
1.23.0 · source

#### pub fn make_ascii_uppercase(&mut self)

Converts this string to its ASCII upper case equivalent in-place.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To return a new uppercased value without modifying the existing one, use `to_ascii_uppercase()`.

##### Examples

    let mut s = String::from("Grüße, Jürgen ❤");

    s.make_ascii_uppercase();

    assert_eq!("GRüßE, JüRGEN ❤", s);

Run
1.23.0 · source

#### pub fn make_ascii_lowercase(&mut self)

Converts this string to its ASCII lower case equivalent in-place.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To return a new lowercased value without modifying the existing one, use `to_ascii_lowercase()`.

##### Examples

    let mut s = String::from("GRÜßE, JÜRGEN ❤");

    s.make_ascii_lowercase();

    assert_eq!("grÜße, jÜrgen ❤", s);

Run
1.34.0 · source

#### pub fn escape_debug(&self) -> EscapeDebug<'_> ⓘ

Return an iterator that escapes each char in `self` with `char::escape_debug`.

Note: only extended grapheme codepoints that begin the string will be escaped.

##### Examples

As an iterator:

    for c in "❤\n!".escape_debug() {
        print!("{c}");
    }
    println!();

Run

Using `println!` directly:

    println!("{}", "❤\n!".escape_debug());

Run

Both are equivalent to:

    println!("❤\\n!");

Run

Using `to_string`:

    assert_eq!("❤\n!".escape_debug().to_string(), "❤\\n!");

Run
1.34.0 · source

#### pub fn escape_default(&self) -> EscapeDefault<'_> ⓘ

Return an iterator that escapes each char in `self` with `char::escape_default`.

##### Examples

As an iterator:

    for c in "❤\n!".escape_default() {
        print!("{c}");
    }
    println!();

Run

Using `println!` directly:

    println!("{}", "❤\n!".escape_default());

Run

Both are equivalent to:

    println!("\\u{{2764}}\\n!");

Run

Using `to_string`:

    assert_eq!("❤\n!".escape_default().to_string(), "\\u{2764}\\n!");

Run
1.34.0 · source

#### pub fn escape_unicode(&self) -> EscapeUnicode<'_> ⓘ

Return an iterator that escapes each char in `self` with `char::escape_unicode`.

##### Examples

As an iterator:

    for c in "❤\n!".escape_unicode() {
        print!("{c}");
    }
    println!();

Run

Using `println!` directly:

    println!("{}", "❤\n!".escape_unicode());

Run

Both are equivalent to:

    println!("\\u{{2764}}\\u{{a}}\\u{{21}}");

Run

Using `to_string`:

    assert_eq!("❤\n!".escape_unicode().to_string(), "\\u{2764}\\u{a}\\u{21}");

Run
source§

### impl str

Methods for string slices.

1.20.0 · source

#### pub fn into_boxed_bytes(self: Box<str>) -> Box<[u8]>

Converts a `Box<str>` into a `Box<[u8]>` without copying or allocating.

##### Examples

    let s = "this is a string";
    let boxed_str = s.to_owned().into_boxed_str();
    let boxed_bytes = boxed_str.into_boxed_bytes();
    assert_eq!(*boxed_bytes, *s.as_bytes());

Run
source

#### pub fn replace<'a, P>(&'a self, from: P, to: &str) -> String where P: Pattern<'a>,

Replaces all matches of a pattern with another string.

`replace` creates a new `String`, and copies the data from this string slice into it. While doing so, it attempts to find matches of a pattern. If it finds any, it replaces them with the replacement string slice.

##### Examples

Basic usage:

    let s = "this is old";

    assert_eq!("this is new", s.replace("old", "new"));
    assert_eq!("than an old", s.replace("is", "an"));

Run

When the pattern doesn’t match, it returns this string slice as `String`:

    let s = "this is old";
    assert_eq!(s, s.replace("cookie monster", "little lamb"));

Run
1.16.0 · source

#### pub fn replacen<'a, P>(&'a self, pat: P, to: &str, count: usize) -> String where P: Pattern<'a>,

Replaces first N matches of a pattern with another string.

`replacen` creates a new `String`, and copies the data from this string slice into it. While doing so, it attempts to find matches of a pattern. If it finds any, it replaces them with the replacement string slice at most `count` times.

##### Examples

Basic usage:

    let s = "foo foo 123 foo";
    assert_eq!("new new 123 foo", s.replacen("foo", "new", 2));
    assert_eq!("faa fao 123 foo", s.replacen('o', "a", 3));
    assert_eq!("foo foo new23 foo", s.replacen(char::is_numeric, "new", 1));

Run

When the pattern doesn’t match, it returns this string slice as `String`:

    let s = "this is old";
    assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));

Run
1.2.0 · source

#### pub fn to_lowercase(&self) -> String

Returns the lowercase equivalent of this string slice, as a new `String`.

‘Lowercase’ is defined according to the terms of the Unicode Derived Core Property `Lowercase`.

Since some characters can expand into multiple characters when changing the case, this function returns a `String` instead of modifying the parameter in-place.

##### Examples

Basic usage:

    let s = "HELLO";

    assert_eq!("hello", s.to_lowercase());

Run

A tricky example, with sigma:

    let sigma = "Σ";

    assert_eq!("σ", sigma.to_lowercase());

    // but at the end of a word, it's ς, not σ:
    let odysseus = "ὈΔΥΣΣΕΎΣ";

    assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());

Run

Languages without case are not changed:

    let new_year = "农历新年";

    assert_eq!(new_year, new_year.to_lowercase());

Run
1.2.0 · source

#### pub fn to_uppercase(&self) -> String

Returns the uppercase equivalent of this string slice, as a new `String`.

‘Uppercase’ is defined according to the terms of the Unicode Derived Core Property `Uppercase`.

Since some characters can expand into multiple characters when changing the case, this function returns a `String` instead of modifying the parameter in-place.

##### Examples

Basic usage:

    let s = "hello";

    assert_eq!("HELLO", s.to_uppercase());

Run

Scripts without case are not changed:

    let new_year = "农历新年";

    assert_eq!(new_year, new_year.to_uppercase());

Run

One character can become multiple:

    let s = "tschüß";

    assert_eq!("TSCHÜSS", s.to_uppercase());

Run
1.4.0 · source

#### pub fn into_string(self: Box<str>) -> String

Converts a `Box<str>` into a `String` without copying or allocating.

##### Examples

    let string = String::from("birthday gift");
    let boxed_str = string.clone().into_boxed_str();

    assert_eq!(boxed_str.into_string(), string);

Run
1.16.0 · source

#### pub fn repeat(&self, n: usize) -> String

Creates a new `String` by repeating a string `n` times.

##### Panics

This function will panic if the capacity would overflow.

##### Examples

Basic usage:

    assert_eq!("abc".repeat(4), String::from("abcabcabcabc"));

Run

A panic upon overflow:

ⓘ

    // this will panic at runtime
    let huge = "0123456789abcdef".repeat(usize::MAX);

Run
1.23.0 · source

#### pub fn to_ascii_uppercase(&self) -> String

Returns a copy of this string where each character is mapped to its ASCII upper case equivalent.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To uppercase the value in-place, use `make_ascii_uppercase`.

To uppercase ASCII characters in addition to non-ASCII characters, use `to_uppercase`.

##### Examples

    let s = "Grüße, Jürgen ❤";

    assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());

Run
1.23.0 · source

#### pub fn to_ascii_lowercase(&self) -> String

Returns a copy of this string where each character is mapped to its ASCII lower case equivalent.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To lowercase the value in-place, use `make_ascii_lowercase`.

To lowercase ASCII characters in addition to non-ASCII characters, use `to_lowercase`.

##### Examples

    let s = "Grüße, Jürgen ❤";

    assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());

Run

## Trait Implementations§

1.14.0 · source§

### impl<'a> Add<&'a str> for Cow<'a, str>

§

#### type Output = Cow<'a, str>

The resulting type after applying the `+` operator.
source§

#### fn add(self, rhs: &'a str) -> <Cow<'a, str> as Add<&'a str>>::Output

Performs the `+` operation. Read more
source§

### impl Add<&str> for String

Implements the `+` operator for concatenating two strings.

This consumes the `String` on the left-hand side and re-uses its buffer (growing it if necessary). This is done to avoid allocating a new `String` and copying the entire contents on every operation, which would lead to O(n^2) running time when building an n-byte string by repeated concatenation.

The string on the right-hand side is only borrowed; its contents are copied into the returned `String`.

#### Examples

Concatenating two `String`s takes the first by value and borrows the second:

    let a = String::from("hello");
    let b = String::from(" world");
    let c = a + &b;
    // `a` is moved and can no longer be used here.

Run

If you want to keep using the first `String`, you can clone it and append to the clone instead:

    let a = String::from("hello");
    let b = String::from(" world");
    let c = a.clone() + &b;
    // `a` is still valid here.

Run

Concatenating `&str` slices can be done by converting the first to a `String`:

    let a = "hello";
    let b = " world";
    let c = a.to_string() + b;

Run
§

#### type Output = String

The resulting type after applying the `+` operator.
source§

#### fn add(self, other: &str) -> String

Performs the `+` operation. Read more
1.14.0 · source§

### impl<'a> AddAssign<&'a str> for Cow<'a, str>

source§

#### fn add_assign(&mut self, rhs: &'a str)

Performs the `+=` operation. Read more
1.12.0 · source§

### impl AddAssign<&str> for String

Implements the `+=` operator for appending to a `String`.

This has the same behavior as the `push_str` method.

source§

#### fn add_assign(&mut self, other: &str)

Performs the `+=` operation. Read more
1.43.0 · source§

### impl AsMut<str> for String

source§

#### fn as_mut(&mut self) -> &mut str

Converts this type into a mutable reference of the (usually inferred) input type.
1.51.0 · source§

### impl AsMut<str> for str

source§

#### fn as_mut(&mut self) -> &mut str

Converts this type into a mutable reference of the (usually inferred) input type.
source§

### impl AsRef<[u8]> for str

source§

#### fn as_ref(&self) -> &[u8] ⓘ

Converts this type into a shared reference of the (usually inferred) input type.
source§

### impl AsRef<OsStr> for str

source§

#### fn as_ref(&self) -> &OsStr

Converts this type into a shared reference of the (usually inferred) input type.
source§

### impl AsRef<Path> for str

source§

#### fn as_ref(&self) -> &Path

Converts this type into a shared reference of the (usually inferred) input type.
1.55.0 · source§

### impl<'a> AsRef<str> for Drain<'a>

source§

#### fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.
source§

### impl AsRef<str> for String

source§

#### fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.
source§

### impl AsRef<str> for str

source§

#### fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.
source§

### impl AsciiExt for str

§

#### type Owned = String

👎Deprecated since 1.26.0: use inherent methods instead
Container type for copied ASCII characters.
source§

#### fn is_ascii(&self) -> bool

👎Deprecated since 1.26.0: use inherent methods instead
Checks if the value is within the ASCII range. Read more
source§

#### fn to_ascii_uppercase(&self) -> Self::Owned

👎Deprecated since 1.26.0: use inherent methods instead
Makes a copy of the value in its ASCII upper case equivalent. Read more
source§

#### fn to_ascii_lowercase(&self) -> Self::Owned

👎Deprecated since 1.26.0: use inherent methods instead
Makes a copy of the value in its ASCII lower case equivalent. Read more
source§

#### fn eq_ignore_ascii_case(&self, o: &Self) -> bool

👎Deprecated since 1.26.0: use inherent methods instead
Checks that two values are an ASCII case-insensitive match. Read more
source§

#### fn make_ascii_uppercase(&mut self)

👎Deprecated since 1.26.0: use inherent methods instead
Converts this type to its ASCII upper case equivalent in-place. Read more
source§

#### fn make_ascii_lowercase(&mut self)

👎Deprecated since 1.26.0: use inherent methods instead
Converts this type to its ASCII lower case equivalent in-place. Read more
source§

### impl Borrow<str> for String

source§

#### fn borrow(&self) -> &str

Immutably borrows from an owned value. Read more
1.36.0 · source§

### impl BorrowMut<str> for String

source§

#### fn borrow_mut(&mut self) -> &mut str

Mutably borrows from an owned value. Read more
1.3.0 · source§

### impl Clone for Box<str>

source§

#### fn clone(&self) -> Box<str>

Returns a copy of the value. Read more
source§

#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
source§

### impl<S> Concat<str> for [S]where S: Borrow<str>,

Note: `str` in `Concat<str>` is not meaningful here. This type parameter of the trait only exists to enable another impl.

§

#### type Output = String

🔬This is a nightly-only experimental API. (`slice_concat_trait` #27747)
The resulting type after concatenation
source§

#### fn concat(slice: &[S]) -> String

🔬This is a nightly-only experimental API. (`slice_concat_trait` #27747)
Implementation of `[T]::concat`
source§

### impl Debug for str

source§

#### fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
1.28.0 · source§

### impl Default for &mut str

source§

#### fn default() -> &mut str

Creates an empty mutable str

source§

### impl Default for &str

source§

#### fn default() -> &str

Creates an empty str

1.17.0 · source§

### impl Default for Box<str>

source§

#### fn default() -> Box<str>

Returns the “default value” for a type. Read more
source§

### impl Display for str

source§

#### fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
source§

### impl !Error for &str

1.30.0 · source§

#### fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any. Read more
source§

#### fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
Read more
source§

#### fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
source§

#### fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (`error_generic_member_access` #99301)
Provides type based access to context intended for error reports. Read more
source§

### impl<'a> Extend<&'a str> for String

source§

#### fn extend<I>(&mut self, iter: I)where I: IntoIterator<Item = &'a str>,

Extends a collection with the contents of an iterator. Read more
source§

#### fn extend_one(&mut self, s: &'a str)

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Extends a collection with exactly one element.
source§

#### fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
1.44.0 · source§

### impl From<&mut str> for String

source§

#### fn from(s: &mut str) -> String

Converts a `&mut str` into a `String`.

The result is allocated on the heap.

1.21.0 · source§

### impl From<&str> for Arc<str>

source§

#### fn from(v: &str) -> Arc<str>

Allocate a reference-counted `str` and copy `v` into it.

##### Example

    let shared: Arc<str> = Arc::from("eggplant");
    assert_eq!("eggplant", &shared[..]);

Run
1.6.0 · source§

### impl From<&str> for Box<dyn Error>

source§

#### fn from(err: &str) -> Box<dyn Error>

Converts a `str` into a box of dyn `Error`.

##### Examples

    use std::error::Error;
    use std::mem;

    let a_str_error = "a str error";
    let a_boxed_error = Box::<dyn Error>::from(a_str_error);
    assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

Run
source§

### impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a>

source§

#### fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a>

Converts a `str` into a box of dyn `Error` + `Send` + `Sync`.

##### Examples

    use std::error::Error;
    use std::mem;

    let a_str_error = "a str error";
    let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error);
    assert!(
        mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

Run
1.17.0 · source§

### impl From<&str> for Box<str>

source§

#### fn from(s: &str) -> Box<str>

Converts a `&str` into a `Box<str>`

This conversion allocates on the heap and performs a copy of `s`.

##### Examples

    let boxed: Box<str> = Box::from("hello");
    println!("{boxed}");

Run
source§

### impl<'a> From<&'a str> for Cow<'a, str>

source§

#### fn from(s: &'a str) -> Cow<'a, str>

Converts a string slice into a `Borrowed` variant. No heap allocation is performed, and the string is not copied.

##### Example

    assert_eq!(Cow::from("eggplant"), Cow::Borrowed("eggplant"));

Run
1.21.0 · source§

### impl From<&str> for Rc<str>

source§

#### fn from(v: &str) -> Rc<str>

Allocate a reference-counted string slice and copy `v` into it.

##### Example

    let shared: Rc<str> = Rc::from("statue");
    assert_eq!("statue", &shared[..]);

Run
source§

### impl From<&str> for String

source§

#### fn from(s: &str) -> String

Converts a `&str` into a `String`.

The result is allocated on the heap.

source§

### impl From<&str> for Vec<u8>

source§

#### fn from(s: &str) -> Vec<u8>

Allocate a `Vec<u8>` and fill it with a UTF-8 string.

##### Examples

    assert_eq!(Vec::from("123"), vec![b'1', b'2', b'3']);

Run
1.45.0 · source§

### impl From<Cow<'_, str>> for Box<str>

source§

#### fn from(cow: Cow<'_, str>) -> Box<str>

Converts a `Cow<'_, str>` into a `Box<str>`

When `cow` is the `Cow::Borrowed` variant, this conversion allocates on the heap and copies the underlying `str`. Otherwise, it will try to reuse the owned `String`’s allocation.

##### Examples

    use std::borrow::Cow;

    let unboxed = Cow::Borrowed("hello");
    let boxed: Box<str> = Box::from(unboxed);
    println!("{boxed}");

Run

    let unboxed = Cow::Owned("hello".to_string());
    let boxed: Box<str> = Box::from(unboxed);
    println!("{boxed}");

Run
1.20.0 · source§

### impl From<String> for Box<str>

source§

#### fn from(s: String) -> Box<str>

Converts the given `String` to a boxed `str` slice that is owned.

##### Examples

    let s1: String = String::from("hello world");
    let s2: Box<str> = Box::from(s1);
    let s3: String = String::from(s2);

    assert_eq!("hello world", s3)

Run
1.12.0 · source§

### impl<'a, 'b> FromIterator<&'b str> for Cow<'a, str>

source§

#### fn from_iter<I>(it: I) -> Cow<'a, str>where I: IntoIterator<Item = &'b str>,

Creates a value from an iterator. Read more
source§

### impl<'a> FromIterator<&'a str> for String

source§

#### fn from_iter<I>(iter: I) -> String where I: IntoIterator<Item = &'a str>,

Creates a value from an iterator. Read more
source§

### impl Hash for str

source§

#### fn hash<H>(&self, state: &mut H)where H: Hasher,

Feeds this value into the given `Hasher`. Read more
source§

### impl<I> Index<I> for str where I: SliceIndex<str>,

§

#### type Output = <I as SliceIndex<str>>::Output

The returned type after indexing.
source§

#### fn index(&self, index: I) -> &<I as SliceIndex<str>>::Output

Performs the indexing (`container[index]`) operation. Read more
source§

### impl<I> IndexMut<I> for str where I: SliceIndex<str>,

source§

#### fn index_mut(&mut self, index: I) -> &mut <I as SliceIndex<str>>::Output

Performs the mutable indexing (`container[index]`) operation. Read more
source§

### impl<S> Join<&str> for [S]where S: Borrow<str>,

§

#### type Output = String

🔬This is a nightly-only experimental API. (`slice_concat_trait` #27747)
The resulting type after concatenation
source§

#### fn join(slice: &[S], sep: &str) -> String

🔬This is a nightly-only experimental API. (`slice_concat_trait` #27747)
Implementation of `[T]::join`
source§

### impl Ord for str

Implements ordering of strings.

Strings are ordered lexicographically by their byte values. This orders Unicode code points based on their positions in the code charts. This is not necessarily the same as “alphabetical” order, which varies by language and locale. Sorting strings according to culturally-accepted standards requires locale-specific data that is outside the scope of the `str` type.

source§

#### fn cmp(&self, other: &str) -> Ordering

This method returns an `Ordering` between `self` and `other`. Read more
source§

### impl<'a, 'b> PartialEq<&'b str> for Cow<'a, str>

source§

#### fn eq(&self, other: &&'b str) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &&'b str) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.29.0 · source§

### impl PartialEq<&str> for OsString

source§

#### fn eq(&self, other: &&str) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl<'a, 'b> PartialEq<&'a str> for String

source§

#### fn eq(&self, other: &&'a str) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &&'a str) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl<'a, 'b> PartialEq<Cow<'a, str>> for &'b str

source§

#### fn eq(&self, other: &Cow<'a, str>) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Cow<'a, str>) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl<'a, 'b> PartialEq<Cow<'a, str>> for str

source§

#### fn eq(&self, other: &Cow<'a, str>) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Cow<'a, str>) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl PartialEq<OsStr> for str

source§

#### fn eq(&self, other: &OsStr) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.29.0 · source§

### impl<'a> PartialEq<OsString> for &'a str

source§

#### fn eq(&self, other: &OsString) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl PartialEq<OsString> for str

source§

#### fn eq(&self, other: &OsString) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl<'a, 'b> PartialEq<String> for &'a str

source§

#### fn eq(&self, other: &String) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &String) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl<'a, 'b> PartialEq<String> for str

source§

#### fn eq(&self, other: &String) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &String) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl<'a, 'b> PartialEq<str> for Cow<'a, str>

source§

#### fn eq(&self, other: &str) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &str) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl PartialEq<str> for OsStr

source§

#### fn eq(&self, other: &str) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl PartialEq<str> for OsString

source§

#### fn eq(&self, other: &str) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl<'a, 'b> PartialEq<str> for String

source§

#### fn eq(&self, other: &str) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &str) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl PartialEq for str

source§

#### fn eq(&self, other: &str) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
source§

#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

### impl PartialOrd<str> for OsStr

source§

#### fn partial_cmp(&self, other: &str) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
source§

#### fn lt(&self, other: &Rhs) -> bool

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more
source§

#### fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
source§

#### fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
source§

#### fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
source§

### impl PartialOrd<str> for OsString

source§

#### fn partial_cmp(&self, other: &str) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
source§

#### fn lt(&self, other: &Rhs) -> bool

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more
source§

#### fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
source§

#### fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
source§

#### fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
source§

### impl PartialOrd for str

Implements comparison operations on strings.

Strings are compared lexicographically by their byte values. This compares Unicode code points based on their positions in the code charts. This is not necessarily the same as “alphabetical” order, which varies by language and locale. Comparing strings according to culturally-accepted standards requires locale-specific data that is outside the scope of the `str` type.

source§

#### fn partial_cmp(&self, other: &str) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
source§

#### fn lt(&self, other: &Rhs) -> bool

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more
source§

#### fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
source§

#### fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
source§

#### fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
source§

### impl<'a, 'b> Pattern<'a> for &'b str

Non-allocating substring search.

Will handle the pattern `""` as returning empty matches at each character boundary.

#### Examples

    assert_eq!("Hello world".find("world"), Some(6));

Run
source§

#### fn is_prefix_of(self, haystack: &'a str) -> bool

🔬This is a nightly-only experimental API. (`pattern` #27721)

Checks whether the pattern matches at the front of the haystack.

source§

#### fn is_contained_in(self, haystack: &'a str) -> bool

🔬This is a nightly-only experimental API. (`pattern` #27721)

Checks whether the pattern matches anywhere in the haystack

source§

#### fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str>

🔬This is a nightly-only experimental API. (`pattern` #27721)

Removes the pattern from the front of haystack, if it matches.

source§

#### fn is_suffix_of(self, haystack: &'a str) -> bool

🔬This is a nightly-only experimental API. (`pattern` #27721)

Checks whether the pattern matches at the back of the haystack.

source§

#### fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>

🔬This is a nightly-only experimental API. (`pattern` #27721)

Removes the pattern from the back of haystack, if it matches.

§

#### type Searcher = StrSearcher<'a, 'b>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Associated searcher for this pattern
source§

#### fn into_searcher(self, haystack: &'a str) -> StrSearcher<'a, 'b>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Constructs the associated searcher from `self` and the `haystack` to search in.
1.73.0 · source§

### impl SliceIndex<str> for (Bound<usize>, Bound<usize>)

Implements substring slicing for arbitrary bounds.

Returns a slice of the given string bounded by the byte indices provided by each bound.

This operation is O(1).

#### Panics

Panics if `begin` or `end` (if it exists and once adjusted for inclusion/exclusion) does not point to the starting byte offset of a character (as defined by `is_char_boundary`), if `begin > end`, or if `end > len`.

§

#### type Output = str

The output type returned by methods.
source§

#### fn get(self, slice: &str) -> Option<&str>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
source§

#### fn get_mut(self, slice: &mut str) -> Option<&mut str>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
source§

#### unsafe fn get_unchecked(self, slice: *const str) -> *const str

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
source§

#### unsafe fn get_unchecked_mut(self, slice: *mut str) -> *mut str

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
source§

#### fn index(self, slice: &str) -> &str

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
source§

#### fn index_mut(self, slice: &mut str) -> &mut str

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.20.0 (const: unstable) · source§

### impl SliceIndex<str> for Range<usize>

Implements substring slicing with syntax `&self[begin .. end]` or `&mut self[begin .. end]`.

Returns a slice of the given string from the byte range [`begin`, `end`).

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of `Index` and `IndexMut`.

#### Panics

Panics if `begin` or `end` does not point to the starting byte offset of a character (as defined by `is_char_boundary`), if `begin > end`, or if `end > len`.

#### Examples

    let s = "Löwe 老虎 Léopard";
    assert_eq!(&s[0 .. 1], "L");

    assert_eq!(&s[1 .. 9], "öwe 老");

    // these will panic:
    // byte 2 lies within `ö`:
    // &s[2 ..3];

    // byte 8 lies within `老`
    // &s[1 .. 8];

    // byte 100 is outside the string
    // &s[3 .. 100];

Run
§

#### type Output = str

The output type returned by methods.
const: unstable · source§

#### fn get(self, slice: &str) -> Option<&<Range<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
const: unstable · source§

#### fn get_mut( self, slice: &mut str ) -> Option<&mut <Range<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
const: unstable · source§

#### unsafe fn get_unchecked( self, slice: *const str ) -> *const <Range<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### unsafe fn get_unchecked_mut( self, slice: *mut str ) -> *mut <Range<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### fn index(self, slice: &str) -> &<Range<usize> as SliceIndex<str>>::Output ⓘ

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
const: unstable · source§

#### fn index_mut( self, slice: &mut str ) -> &mut <Range<usize> as SliceIndex<str>>::Output ⓘ

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.20.0 (const: unstable) · source§

### impl SliceIndex<str> for RangeFrom<usize>

Implements substring slicing with syntax `&self[begin ..]` or `&mut self[begin ..]`.

Returns a slice of the given string from the byte range [`begin`, `len`). Equivalent to `&self[begin .. len]` or `&mut self[begin .. len]`.

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of `Index` and `IndexMut`.

#### Panics

Panics if `begin` does not point to the starting byte offset of a character (as defined by `is_char_boundary`), or if `begin > len`.

§

#### type Output = str

The output type returned by methods.
const: unstable · source§

#### fn get( self, slice: &str ) -> Option<&<RangeFrom<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
const: unstable · source§

#### fn get_mut( self, slice: &mut str ) -> Option<&mut <RangeFrom<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
const: unstable · source§

#### unsafe fn get_unchecked( self, slice: *const str ) -> *const <RangeFrom<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### unsafe fn get_unchecked_mut( self, slice: *mut str ) -> *mut <RangeFrom<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### fn index(self, slice: &str) -> &<RangeFrom<usize> as SliceIndex<str>>::Output ⓘ

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
const: unstable · source§

#### fn index_mut( self, slice: &mut str ) -> &mut <RangeFrom<usize> as SliceIndex<str>>::Output ⓘ

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.20.0 (const: unstable) · source§

### impl SliceIndex<str> for RangeFull

Implements substring slicing with syntax `&self[..]` or `&mut self[..]`.

Returns a slice of the whole string, i.e., returns `&self` or `&mut self`. Equivalent to `&self[0 .. len]` or `&mut self[0 .. len]`. Unlike other indexing operations, this can never panic.

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of `Index` and `IndexMut`.

Equivalent to `&self[0 .. len]` or `&mut self[0 .. len]`.

§

#### type Output = str

The output type returned by methods.
const: unstable · source§

#### fn get(self, slice: &str) -> Option<&<RangeFull as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
const: unstable · source§

#### fn get_mut( self, slice: &mut str ) -> Option<&mut <RangeFull as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
const: unstable · source§

#### unsafe fn get_unchecked( self, slice: *const str ) -> *const <RangeFull as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### unsafe fn get_unchecked_mut( self, slice: *mut str ) -> *mut <RangeFull as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### fn index(self, slice: &str) -> &<RangeFull as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
const: unstable · source§

#### fn index_mut( self, slice: &mut str ) -> &mut <RangeFull as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.26.0 (const: unstable) · source§

### impl SliceIndex<str> for RangeInclusive<usize>

Implements substring slicing with syntax `&self[begin ..= end]` or `&mut self[begin ..= end]`.

Returns a slice of the given string from the byte range [`begin`, `end`]. Equivalent to `&self [begin .. end + 1]` or `&mut self[begin .. end + 1]`, except if `end` has the maximum value for `usize`.

This operation is O(1).

#### Panics

Panics if `begin` does not point to the starting byte offset of a character (as defined by `is_char_boundary`), if `end` does not point to the ending byte offset of a character (`end + 1` is either a starting byte offset or equal to `len`), if `begin > end`, or if `end >= len`.

§

#### type Output = str

The output type returned by methods.
const: unstable · source§

#### fn get( self, slice: &str ) -> Option<&<RangeInclusive<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
const: unstable · source§

#### fn get_mut( self, slice: &mut str ) -> Option<&mut <RangeInclusive<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
const: unstable · source§

#### unsafe fn get_unchecked( self, slice: *const str ) -> *const <RangeInclusive<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### unsafe fn get_unchecked_mut( self, slice: *mut str ) -> *mut <RangeInclusive<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### fn index( self, slice: &str ) -> &<RangeInclusive<usize> as SliceIndex<str>>::Output ⓘ

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
const: unstable · source§

#### fn index_mut( self, slice: &mut str ) -> &mut <RangeInclusive<usize> as SliceIndex<str>>::Output ⓘ

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.20.0 (const: unstable) · source§

### impl SliceIndex<str> for RangeTo<usize>

Implements substring slicing with syntax `&self[.. end]` or `&mut self[.. end]`.

Returns a slice of the given string from the byte range [0, `end`). Equivalent to `&self[0 .. end]` or `&mut self[0 .. end]`.

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of `Index` and `IndexMut`.

#### Panics

Panics if `end` does not point to the starting byte offset of a character (as defined by `is_char_boundary`), or if `end > len`.

§

#### type Output = str

The output type returned by methods.
const: unstable · source§

#### fn get( self, slice: &str ) -> Option<&<RangeTo<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
const: unstable · source§

#### fn get_mut( self, slice: &mut str ) -> Option<&mut <RangeTo<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
const: unstable · source§

#### unsafe fn get_unchecked( self, slice: *const str ) -> *const <RangeTo<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### unsafe fn get_unchecked_mut( self, slice: *mut str ) -> *mut <RangeTo<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### fn index(self, slice: &str) -> &<RangeTo<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
const: unstable · source§

#### fn index_mut( self, slice: &mut str ) -> &mut <RangeTo<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.26.0 (const: unstable) · source§

### impl SliceIndex<str> for RangeToInclusive<usize>

Implements substring slicing with syntax `&self[..= end]` or `&mut self[..= end]`.

Returns a slice of the given string from the byte range [0, `end`]. Equivalent to `&self [0 .. end + 1]`, except if `end` has the maximum value for `usize`.

This operation is O(1).

#### Panics

Panics if `end` does not point to the ending byte offset of a character (`end + 1` is either a starting byte offset as defined by `is_char_boundary`, or equal to `len`), or if `end >= len`.

§

#### type Output = str

The output type returned by methods.
const: unstable · source§

#### fn get( self, slice: &str ) -> Option<&<RangeToInclusive<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
const: unstable · source§

#### fn get_mut( self, slice: &mut str ) -> Option<&mut <RangeToInclusive<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
const: unstable · source§

#### unsafe fn get_unchecked( self, slice: *const str ) -> *const <RangeToInclusive<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### unsafe fn get_unchecked_mut( self, slice: *mut str ) -> *mut <RangeToInclusive<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
const: unstable · source§

#### fn index( self, slice: &str ) -> &<RangeToInclusive<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
const: unstable · source§

#### fn index_mut( self, slice: &mut str ) -> &mut <RangeToInclusive<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
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### impl ToOwned for str

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#### type Owned = String

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> String

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut String)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl ToSocketAddrs for str

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#### type Iter = IntoIter<SocketAddr>

Returned iterator over socket addresses which this type may correspond to.
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#### fn to_socket_addrs(&self) -> Result<IntoIter<SocketAddr>>

Converts this object to an iterator of resolved `SocketAddr`s. Read more
1.72.0 · source§

### impl<'a> TryFrom<&'a OsStr> for &'a str

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#### fn try_from(value: &'a OsStr) -> Result<Self, Self::Error>

Tries to convert an `&OsStr` to a `&str`.

    use std::ffi::OsStr;

    let os_str = OsStr::new("foo");
    let as_str = <&str>::try_from(os_str).unwrap();
    assert_eq!(as_str, "foo");

Run
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#### type Error = Utf8Error

The type returned in the event of a conversion error.
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### impl ConstParamTy for str

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### impl Eq for str

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### impl StructuralEq for str

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### impl StructuralPartialEq for str

## Auto Trait Implementations§

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### impl RefUnwindSafe for str

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### impl Send for str

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### impl !Sized for str

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### impl Sync for str

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### impl Unpin for str

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### impl UnwindSafe for str

## Blanket Implementations§

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### impl<T> Any for Twhere T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for Twhere T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for Twhere T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> ToString for Twhere T: Display + ?Sized,

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#### default fn to_string(&self) -> String

Converts the given value to a `String`. Read more