polars.concat_list¶
- polars.concat_list(exprs: Union[Sequence[Union[str, polars.internals.expr.Expr, polars.internals.series.Series]], polars.internals.expr.Expr]) polars.internals.expr.Expr ¶
Concat the arrays in a Series dtype List in linear time.
- Parameters
- exprs
Columns to concat into a List Series
Examples
Create lagged columns and collect them into a list. This mimics a rolling window.
>>> df = pl.DataFrame( ... { ... "A": [1.0, 2.0, 9.0, 2.0, 13.0], ... } ... ) >>> ( ... df.with_columns( ... [pl.col("A").shift(i).alias(f"A_lag_{i}") for i in range(3)] ... ).select( ... [ ... pl.concat_list([f"A_lag_{i}" for i in range(3)][::-1]).alias( ... "A_rolling" ... ) ... ] ... ) ... ) shape: (5, 1) ┌─────────────────┐ │ A_rolling │ │ --- │ │ list [f64] │ ╞═════════════════╡ │ [null, null, 1] │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤ │ [null, 1, 2] │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤ │ [1, 2, 9] │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤ │ [2, 9, 2] │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤ │ [9, 2, 13] │ └─────────────────┘