Function validate_indices

pandas/core/indexers/utils.py:189–234

Perform bounds-checking for an indexer. -1 is allowed for indicating missing values. Parameters ---------- indices : ndarray n : int Length of the array being indexed. Raises ------ ValueError Examples -------- >>> validate_indices(np.arra

(indices: np.ndarray, n: int)

def validate_indices(indices: np.ndarray, n: int) -> None:
    """
    Perform bounds-checking for an indexer.

    -1 is allowed for indicating missing values.

    Parameters
    ----------
    indices : ndarray
    n : int
        Length of the array being indexed.

    Raises
    ------
    ValueError

    Examples
    --------
    >>> validate_indices(np.array([1, 2]), 3)  # OK

    >>> validate_indices(np.array([1, -2]), 3)
    Traceback (most recent call last):
        ...
    ValueError: negative dimensions are not allowed

    >>> validate_indices(np.array([1, 2, 3]), 3)
    Traceback (most recent call last):
        ...
    IndexError: indices are out-of-bounds

    >>> validate_indices(np.array([-1, -1]), 0)  # OK

    >>> validate_indices(np.array([0, 1]), 0)
    Traceback (most recent call last):
        ...
    IndexError: indices are out-of-bounds
    """
    if len(indices):
        min_idx = indices.min()
        if min_idx < -1:
            msg = f"'indices' contains values less than allowed ({min_idx} < -1)"
            raise ValueError(msg)

        max_idx = indices.max()
        if max_idx >= n:
            raise IndexError("indices are out-of-bounds")


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