polars.Expr.alias#
- Expr.alias(name: str) Expr [source]#
Rename the expression.
- Parameters:
- name
The new name.
See also
Examples
Rename an expression to avoid overwriting an existing column.
>>> df = pl.DataFrame( ... { ... "a": [1, 2, 3], ... "b": ["x", "y", "z"], ... } ... ) >>> df.with_columns( ... pl.col("a") + 10, ... pl.col("b").str.to_uppercase().alias("c"), ... ) shape: (3, 3) ┌─────┬─────┬─────┐ │ a ┆ b ┆ c │ │ --- ┆ --- ┆ --- │ │ i64 ┆ str ┆ str │ ╞═════╪═════╪═════╡ │ 11 ┆ x ┆ X │ │ 12 ┆ y ┆ Y │ │ 13 ┆ z ┆ Z │ └─────┴─────┴─────┘
Overwrite the default name of literal columns to prevent errors due to duplicate column names.
>>> df.with_columns( ... pl.lit(True).alias("c"), ... pl.lit(4.0).alias("d"), ... ) shape: (3, 4) ┌─────┬─────┬──────┬─────┐ │ a ┆ b ┆ c ┆ d │ │ --- ┆ --- ┆ --- ┆ --- │ │ i64 ┆ str ┆ bool ┆ f64 │ ╞═════╪═════╪══════╪═════╡ │ 1 ┆ x ┆ true ┆ 4.0 │ │ 2 ┆ y ┆ true ┆ 4.0 │ │ 3 ┆ z ┆ true ┆ 4.0 │ └─────┴─────┴──────┴─────┘