30 lines
770 B
Markdown
Vendored
30 lines
770 B
Markdown
Vendored
[//]: # (title: group)
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<!---IMPORT org.jetbrains.kotlinx.dataframe.samples.api.Modify-->
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Group columns into [`ColumnsGroups`](DataColumn.md#columngroup).
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```text
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group { columns }
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.into(groupName) | .into { groupNameExpression }
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groupNameExpression = DataColumn.(DataColumn) -> String
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```
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**Reverse operation:** [`ungroup`](ungroup.md), [`flatten`](flatten.md)
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It is a special case of [`move`](move.md) operation.
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See [column selectors](ColumnSelectors.md) for how to select the columns for this operation.
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<!---FUN group-->
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```kotlin
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df.group { age and city }.into("info")
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df.group { all() }.into { it.type().toString() }.print()
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```
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<inline-frame src="resources/org.jetbrains.kotlinx.dataframe.samples.api.Modify.group.html" width="100%"/>
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<!---END-->
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