[//]: # (title: add)

<!---IMPORT org.jetbrains.kotlinx.dataframe.samples.api.Modify-->

Returns [`DataFrame`](DataFrame.md) with union of columns from several given [`DataFrame`](DataFrame.md) objects.

<!---FUN addDataFrames-->

```kotlin
df.addAll(df1, df2)
```

<inline-frame src="resources/org.jetbrains.kotlinx.dataframe.samples.api.Modify.addDataFrames.html" width="100%"/>
<!---END-->

See [all use cases of 'add' operation](add.md).