polars.Expr.cast#

Expr.cast(dtype: Union[Type[DataType], DataType, type[Any]], strict: bool = True) Expr[source]#

Cast between data types.

Parameters:
dtype

DataType to cast to.

strict

Throw an error if a cast could not be done. For instance, due to an overflow.

Examples

>>> df = pl.DataFrame(
...     {
...         "a": [1, 2, 3],
...         "b": ["4", "5", "6"],
...     }
... )
>>> df.with_columns(
...     [
...         pl.col("a").cast(pl.Float64),
...         pl.col("b").cast(pl.Int32),
...     ]
... )
shape: (3, 2)
┌─────┬─────┐
│ a   ┆ b   │
│ --- ┆ --- │
│ f64 ┆ i32 │
╞═════╪═════╡
│ 1.0 ┆ 4   │
├╌╌╌╌╌┼╌╌╌╌╌┤
│ 2.0 ┆ 5   │
├╌╌╌╌╌┼╌╌╌╌╌┤
│ 3.0 ┆ 6   │
└─────┴─────┘