polars.Expr.pow#
- Expr.pow(exponent: IntoExprColumn | int | float) Expr [source]#
Method equivalent of exponentiation operator
expr ** exponent
.If the exponent is float, the result follows the dtype of exponent. Otherwise, it follows dtype of base.
- Parameters:
- exponent
Numeric literal or expression exponent value.
Examples
>>> df = pl.DataFrame({"x": [1, 2, 4, 8]}) >>> df.with_columns( ... pl.col("x").pow(3).alias("cube"), ... pl.col("x").pow(pl.col("x").log(2)).alias("x ** xlog2"), ... ) shape: (4, 3) ┌─────┬──────┬────────────┐ │ x ┆ cube ┆ x ** xlog2 │ │ --- ┆ --- ┆ --- │ │ i64 ┆ i64 ┆ f64 │ ╞═════╪══════╪════════════╡ │ 1 ┆ 1 ┆ 1.0 │ │ 2 ┆ 8 ┆ 2.0 │ │ 4 ┆ 64 ┆ 16.0 │ │ 8 ┆ 512 ┆ 512.0 │ └─────┴──────┴────────────┘
Raising an integer to a positive integer results in an integer - in order to raise to a negative integer, you can cast either the base or the exponent to float first:
>>> df.with_columns( ... x_squared=pl.col("x").pow(2), ... x_inverse=pl.col("x").pow(-1.0), ... ) shape: (4, 3) ┌─────┬───────────┬───────────┐ │ x ┆ x_squared ┆ x_inverse │ │ --- ┆ --- ┆ --- │ │ i64 ┆ i64 ┆ f64 │ ╞═════╪═══════════╪═══════════╡ │ 1 ┆ 1 ┆ 1.0 │ │ 2 ┆ 4 ┆ 0.5 │ │ 4 ┆ 16 ┆ 0.25 │ │ 8 ┆ 64 ┆ 0.125 │ └─────┴───────────┴───────────┘