39 lines
1 KiB
Python
39 lines
1 KiB
Python
|
from __future__ import annotations
|
||
|
|
|
||
|
|
from typing import Generic
|
||
|
|
|
||
|
|
from narwhals.typing import SeriesT
|
||
|
|
|
||
|
|
|
||
|
|
class SeriesListNamespace(Generic[SeriesT]):
|
||
|
|
def __init__(self, series: SeriesT) -> None:
|
||
|
|
self._narwhals_series = series
|
||
|
|
|
||
|
|
def len(self) -> SeriesT:
|
||
|
|
"""Return the number of elements in each list.
|
||
|
|
|
||
|
|
Null values count towards the total.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
A new series.
|
||
|
|
|
||
|
|
Examples:
|
||
|
|
>>> import pyarrow as pa
|
||
|
|
>>> import narwhals as nw
|
||
|
|
>>> s_native = pa.chunked_array([[[1, 2], [3, 4, None], None, []]])
|
||
|
|
>>> s = nw.from_native(s_native, series_only=True)
|
||
|
|
>>> s.list.len().to_native() # doctest: +ELLIPSIS
|
||
|
|
<pyarrow.lib.ChunkedArray object at ...>
|
||
|
|
[
|
||
|
|
[
|
||
|
|
2,
|
||
|
|
3,
|
||
|
|
null,
|
||
|
|
0
|
||
|
|
]
|
||
|
|
]
|
||
|
|
"""
|
||
|
|
return self._narwhals_series._with_compliant(
|
||
|
|
self._narwhals_series._compliant_series.list.len()
|
||
|
|
)
|