polars.Series.replace

Series.replace(
    old: IntoExpr | Sequence[Any] | Mapping[Any,
    Any],
    new: IntoExpr | Sequence[Any] | NoDefault = <no_default>,
    *,
    default: IntoExpr | NoDefault = <no_default>,
    return_dtype: PolarsDataType | None = None,
) → Self

Replace values by different values of the same data type.

Parameters:

old

Value or sequence of values to replace. Also accepts a mapping of values to their replacement as syntactic sugar for replace(old=Series(mapping.keys()), new=Series(mapping.values())).

new

Value or sequence of values to replace by. Length must match the length of old or have length 1.

default

Set values that were not replaced to this value. Defaults to keeping the original value. Accepts expression input. Non-expression inputs are parsed as literals.

Deprecated since version 0.20.31: Use replace_strict() instead to set a default while replacing values.

return_dtype

The data type of the resulting expression. If set to None (default), the data type is determined automatically based on the other inputs.

Deprecated since version 0.20.31: Use replace_strict() instead to set a return data type while replacing values.

See also

replace_strict

str.replace

Examples

Replace a single value by another value. Values that were not replaced remain unchanged.

>>> s = pl.Series([1, 2, 2, 3])
>>> s.replace(2, 100)
shape: (4,)
Series: '' [i64]
[
    1
    100
    100
    3
]

Replace multiple values by passing sequences to the old and new parameters.

>>> s.replace([2, 3], [100, 200])
shape: (4,)
Series: '' [i64]
[
    1
    100
    100
    200
]

Passing a mapping with replacements is also supported as syntactic sugar.

>>> mapping = {2: 100, 3: 200}
>>> s.replace(mapping)
shape: (4,)
Series: '' [i64]
[
    1
    100
    100
    200
]

The original data type is preserved when replacing by values of a different data type. Use replace_strict() to replace and change the return data type.

>>> s = pl.Series(["x", "y", "z"])
>>> mapping = {"x": 1, "y": 2, "z": 3}
>>> s.replace(mapping)
shape: (3,)
Series: '' [str]
[
    "1"
    "2"
    "3"
]