Function apply

python/pathway/internals/common.py:96–129

Applies function to column expressions, column-wise. Output column type deduced from type-annotations of a function. Example: >>> import pathway as pw >>> def concat(left: str, right: str) -> str: ... return left+right >>> t1 = pw.debug.table_from_markdown(''' ... age

(
    fun: Callable,
    *args: expr.ColumnExpression | Value,
    **kwargs: expr.ColumnExpression | Value,
)

@check_arg_types
@trace_user_frame
def apply(
    fun: Callable,
    *args: expr.ColumnExpression | Value,
    **kwargs: expr.ColumnExpression | Value,
) -> expr.ColumnExpression:
    """Applies function to column expressions, column-wise.
    Output column type deduced from type-annotations of a function.

    Example:

    >>> import pathway as pw
    >>> def concat(left: str, right: str) -> str:
    ...   return left+right
    >>> t1 = pw.debug.table_from_markdown('''
    ... age  owner  pet
    ...  10  Alice  dog
    ...   9    Bob  dog
    ...   8  Alice  cat
    ...   7    Bob  dog''')
    >>> t2 = t1.select(col = pw.apply(concat, t1.owner, t1.pet))
    >>> pw.debug.compute_and_print(t2, include_id=False)
    col
    Alicecat
    Alicedog
    Bobdog
    Bobdog
    """
    if kwargs:
        warn(
            "Passing keyword arguments to the function in pw.apply is deprecated. Use positional arguments instead.",
            DeprecationWarning,
            stacklevel=5,
        )
    return udf(fun)(*args, **kwargs)


def apply_with_type(