polars.Expr.len

Expr.len() → Expr

Return the number of elements in the column.

Null values count towards the total.

Returns:

Expr

Expression of data type UInt32.

See also

count

Examples

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