Removed removeColumns argument from aggregateGroupBy, as it is always true

Author: Jolanrensen

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/aggregate.kt

@@ -21,4 +21,8 @@ public fun <T, R> Pivot<T>.aggregate(separate: Boolean = false, body: Selector<A
 @Refine
 @Interpretable("Aggregate")
 public fun <T, R> Grouped<T>.aggregate(body: AggregateGroupedBody<T, R>): DataFrame<T> =
-    aggregateGroupBy((this as GroupBy<*, *>).toDataFrame(), { groups.cast() }, removeColumns = true, body).cast<T>()
+    aggregateGroupBy(
+        df = (this as GroupBy<*, *>).toDataFrame(),
+        selector = { groups.cast() },
+        body = body,
+    ).cast()

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/GroupByImpl.kt

@@ -75,7 +75,6 @@ internal class GroupByImpl<T, G>(
 internal fun <T, G, R> aggregateGroupBy(
     df: DataFrame<T>,
     selector: ColumnSelector<T, DataFrame<G>?>,
-    removeColumns: Boolean,
     body: AggregateGroupedBody<G, R>,
 ): DataFrame<T> {
     val defaultAggregateName = "aggregated"
@@ -126,13 +125,11 @@ internal fun <T, G, R> aggregateGroupBy(
     val removedNode = removed.removedColumns.single()
     val insertPath = removedNode.pathFromRoot().dropLast(1)
 
-    if (!removeColumns) removedNode.data.wasRemoved = false
-
     val columnsToInsert = groupedFrame.getColumnsWithPaths {
         colsAtAnyDepth().filter { !it.isColumnGroup() }
     }.map {
         ColumnToInsert(insertPath + it.path, it, removedNode)
     }
-    val src = if (removeColumns) removed.df else df
-    return src.insertImpl(columnsToInsert)
+
+    return removed.df.insertImpl(columnsToInsert)
 }