polars.Expr.len

Expr.len() → Self

Return the number of elements in the column.

Null values are treated like regular elements in this context.

Alias for count().

Examples

>>> df = pl.DataFrame({"a": [8, 9, 10], "b": [None, 4, 4]})
>>> df.select(pl.all().len())
shape: (1, 2)
┌─────┬─────┐
│ a   ┆ b   │
│ --- ┆ --- │
│ u32 ┆ u32 │
╞═════╪═════╡
│ 3   ┆ 3   │
└─────┴─────┘