How to select columns by data type in Polars?

Question

In pandas we have the pandas.DataFrame.select_dtypes method that selects certain columns depending on the dtype. Is there a similar way to do such a thing in Polars?

Answer 1

One can pass a data type to pl.col:

import polars as pl

df = pl.DataFrame(
    {
        "id": [1, 2, 3],
        "name": ["John", "Jane", "Jake"],
        "else": [10.0, 20.0, 30.0],
    }
)
print(df.select([pl.col(pl.String), pl.col(pl.Int64)]))

Output:

shape: (3, 2)
┌──────┬─────┐
│ name ┆ id  │
│ ---  ┆ --- │
│ str  ┆ i64 │
╞══════╪═════╡
│ John ┆ 1   │
│ Jane ┆ 2   │
│ Jake ┆ 3   │
└──────┴─────┘