polars.testing.parametric.create_list_strategy#

polars.testing.parametric.create_list_strategy( inner_dtype: PolarsDataType | None, select_from: Sequence[Any] | None = None, size: int | None = None, min_size: int | None = None, max_size: int | None = None, unique: bool = False, ) → SearchStrategy[list[Any]][source]#

Hypothesis strategy for producing polars List data.

Parameters:

inner_dtypePolarsDataType: type of the inner list elements (can also be another List).
select_fromlist, optional: randomly select the innermost values from this list (otherwise the default strategy associated with the innermost dtype is used).
sizeint, optional: if set, generated lists will be of exactly this size (and ignore the min_size/max_size params).
min_sizeint, optional: set the minimum size of the generated lists (default: 0 if unset).
max_sizeint, optional: set the maximum size of the generated lists (default: 3 if min_size is unset or zero, otherwise 2x min_size).
uniquebool, optional: ensure that the generated lists contain unique values.

Examples

Create a strategy that generates a list of i32 values:

>>> lst = create_list_strategy(inner_dtype=pl.Int32)
>>> lst.example()  
[-11330, 24030, 116]

Create a strategy that generates lists of lists of specific strings:

>>> lst = create_list_strategy(
...     inner_dtype=pl.List(pl.Utf8),
...     select_from=["xx", "yy", "zz"],
... )
>>> lst.example()  
[['yy', 'xx'], [], ['zz']]

Create a UInt8 dtype strategy as a hypothesis composite that generates pairs of small int values where the first is always <= the second:

>>> from hypothesis.strategies import composite
>>>
>>> @composite
... def uint8_pairs(draw, uints=create_list_strategy(pl.UInt8, size=2)):
...     pairs = list(zip(draw(uints), draw(uints)))
...     return [sorted(ints) for ints in pairs]
...
>>> uint8_pairs().example()  
[(12, 22), (15, 131)]
>>> uint8_pairs().example()  
[(59, 176), (149, 149)]