Meta

The following methods are available under the expr.meta attribute.

Expr.meta.has_multiple_outputs()	Whether this expression expands into multiple expressions.
Expr.meta.is_regex_projection()	Whether this expression expands to columns that match a regex pattern.
Expr.meta.output_name()	Get the column name that this expression would produce.
Expr.meta.pop()	Pop the latest expression and return the input(s) of the popped expression.
Expr.meta.root_names()	Get a list with the root column name.
Expr.meta.undo_aliases()	Undo any renaming operation like alias or keep_name.