def udwf()

in python/datafusion/udf.py [0:0]

• 4 lines of code
• 3 McCabe index (conditional complexity)

    def udwf(*args: Any, **kwargs: Any):  # noqa: D417
        """Create a new User-Defined Window Function (UDWF).

        This class can be used both as a **function** and as a **decorator**.

        Usage:
            - **As a function**: Call `udwf(func, input_types, return_type, volatility,
              name)`.
            - **As a decorator**: Use `@udwf(input_types, return_type, volatility,
              name)`. When using `udwf` as a decorator, **do not pass `func`
              explicitly**.

        **Function example:**
            ```
            import pyarrow as pa

            class BiasedNumbers(WindowEvaluator):
                def __init__(self, start: int = 0) -> None:
                    self.start = start

                def evaluate_all(self, values: list[pa.Array],
                    num_rows: int) -> pa.Array:
                    return pa.array([self.start + i for i in range(num_rows)])

            def bias_10() -> BiasedNumbers:
                return BiasedNumbers(10)

            udwf1 = udwf(BiasedNumbers, pa.int64(), pa.int64(), "immutable")
            udwf2 = udwf(bias_10, pa.int64(), pa.int64(), "immutable")
            udwf3 = udwf(lambda: BiasedNumbers(20), pa.int64(), pa.int64(), "immutable")

            ```

        **Decorator example:**
            ```
            @udwf(pa.int64(), pa.int64(), "immutable")
            def biased_numbers() -> BiasedNumbers:
                return BiasedNumbers(10)
            ```

        Args:
            func: **Only needed when calling as a function. Skip this argument when
                using `udwf` as a decorator.**
            input_types: The data types of the arguments.
            return_type: The data type of the return value.
            volatility: See :py:class:`Volatility` for allowed values.
            name: A descriptive name for the function.

        Returns:
            A user-defined window function that can be used in window function calls.
        """
        if args and callable(args[0]):
            # Case 1: Used as a function, require the first parameter to be callable
            return WindowUDF._create_window_udf(*args, **kwargs)
        # Case 2: Used as a decorator with parameters
        return WindowUDF._create_window_udf_decorator(*args, **kwargs)