Update usages of dataFrameOf(vararg columns: AnyBaseCol) in samples

Author: koperagen

core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api/Analyze.kt

@@ -539,11 +539,12 @@ class Analyze : TestBase() {
     @TransformDataFrameExpressions
     fun dataFrameToGroupBy() {
         // SampleStart
-        val key by columnOf(1, 2) // create int column with name "key"
-        val data by columnOf(df[0..3], df[4..6]) // create frame column with name "data"
-        val df = dataFrameOf(key, data) // create dataframe with two columns
+        val df = dataFrameOf(
+            "key" to columnOf(1, 2),
+            "data" to columnOf(df[0..3], df[4..6]),
+        ) // create dataframe with two columns
 
-        df.asGroupBy { data } // convert dataframe to GroupBy by interpreting 'data' column as groups
+        df.asGroupBy("data") // convert dataframe to GroupBy by interpreting 'data' column as groups
         // SampleEnd
     }
 

core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api/Modify.kt

@@ -648,11 +648,11 @@ class Modify : TestBase() {
     @TransformDataFrameExpressions
     fun explodeSeveral() {
         // SampleStart
-        val a by columnOf(listOf(1, 2), listOf(3, 4, 5))
-        val b by columnOf(listOf(1, 2, 3), listOf(4, 5))
-
-        val df = dataFrameOf(a, b)
-        df.explode { a and b }
+        val df = dataFrameOf(
+            "a" to columnOf(listOf(1, 2), listOf(3, 4, 5)),
+            "b" to columnOf(listOf(1, 2, 3), listOf(4, 5)),
+        )
+        df.explode("a", "b")
         // SampleEnd
     }
 

docs/StardustDocs/topics/explode.md

@@ -49,11 +49,11 @@ When several columns are exploded in one operation, lists in different columns w
 <!---FUN explodeSeveral-->
 
 ```kotlin
-val a by columnOf(listOf(1, 2), listOf(3, 4, 5))
-val b by columnOf(listOf(1, 2, 3), listOf(4, 5))
-
-val df = dataFrameOf(a, b)
-df.explode { a and b }
+val df = dataFrameOf(
+    "a" to columnOf(listOf(1, 2), listOf(3, 4, 5)),
+    "b" to columnOf(listOf(1, 2, 3), listOf(4, 5)),
+)
+df.explode("a", "b")
 ```
 
 <!---END-->

docs/StardustDocs/topics/groupBy.md

@@ -111,11 +111,12 @@ Any [`DataFrame`](DataFrame.md) with `FrameColumn` can be reinterpreted as `Grou
 <!---FUN dataFrameToGroupBy-->
 
 ```kotlin
-val key by columnOf(1, 2) // create int column with name "key"
-val data by columnOf(df[0..3], df[4..6]) // create frame column with name "data"
-val df = dataFrameOf(key, data) // create dataframe with two columns
+val df = dataFrameOf(
+    "key" to columnOf(1, 2),
+    "data" to columnOf(df[0..3], df[4..6]),
+) // create dataframe with two columns
 
-df.asGroupBy { data } // convert dataframe to GroupBy by interpreting 'data' column as groups
+df.asGroupBy("data") // convert dataframe to GroupBy by interpreting 'data' column as groups
 ```
 
 <!---END-->