df-research/dataframe/docs/StardustDocs/topics/flatten.md

Returns DataFrame without column groupings under selected columns.

flatten  [ { columns } ]

Columns will keep their original names after flattening. Potential column name clashes are resolved by adding minimal possible name prefix from ancestor columns.

Related operations:

See column selectors for how to select the columns for this operation.

// name.firstName -> firstName
// name.lastName -> lastName
df.flatten { name }

// name.firstName -> firstName
// name.lastName -> lastName
df.flatten("name")

To remove all column groupings in DataFrame, invoke flatten without parameters:

df.flatten()