polars.Series.__setitem__#

Series.__setitem__(
key: int | Series | ndarray[Any, Any] | Sequence[object] | tuple[object],
value: Any,
) → None[source]#

Set Series values in-place using a single index, boolean mask, or index array.

Parameters:
key

Determines which elements to update:

  • int: a single row index.

  • Series (Boolean): a boolean mask.

  • Series (Integer): an index array.

  • ndarray: a NumPy boolean mask or integer index array.

  • list / tuple: an index sequence (cast to UInt32).

value

Scalar or sequence of values to assign.

Examples

Set a single element by index:

>>> s = pl.Series("a", [1, 2, 3])
>>> s[0] = 10
>>> s
shape: (3,)
Series: 'a' [i64]
[
    10
    2
    3
]

Set elements with a boolean mask:

>>> s[pl.Series([False, True, True])] = 99
>>> s
shape: (3,)
Series: 'a' [i64]
[
    10
    99
    99
]
On this page