Function len

Example

>>> const df = pl.DataFrame(
...     {
...         "a": [1, 2, None],
...         "b": [3, None, None],
...         "c": ["foo", "bar", "foo"],
...     }
... )
>>> df.select(pl.len())
shape: (1, 1)
┌─────┐
│ len │
│ --- │
│ u32 │
╞═════╡
│ 3   │
└─────┘
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Generate an index column by using len in conjunction with :func:intRange.

>>> df.select(
...     pl.intRange(pl.len(), dtype=pl.UInt32).alias("index"),
...     pl.all(),
... )
shape: (3, 4)
┌───────┬──────┬──────┬─────┐
│ index ┆ a    ┆ b    ┆ c   │
│ ---   ┆ ---  ┆ ---  ┆ --- │
│ u32   ┆ i64  ┆ i64  ┆ str │
╞═══════╪══════╪══════╪═════╡
│ 0     ┆ 1    ┆ 3    ┆ foo │
│ 1     ┆ 2    ┆ null ┆ bar │
│ 2     ┆ null ┆ null ┆ foo │
└───────┴──────┴──────┴─────┘
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