Function _unique

sklearn/utils/_encode.py:14–52

Helper function to find unique values with support for python objects. Uses pure python method for object dtype, and numpy method for all other dtypes. Parameters ---------- values : ndarray Values to check for unknowns. return_inverse : bool, default=False

(values, *, return_inverse=False, return_counts=False)

def _unique(values, *, return_inverse=False, return_counts=False):
    """Helper function to find unique values with support for python objects.

    Uses pure python method for object dtype, and numpy method for
    all other dtypes.

    Parameters
    ----------
    values : ndarray
        Values to check for unknowns.

    return_inverse : bool, default=False
        If True, also return the indices of the unique values.

    return_counts : bool, default=False
        If True, also return the number of times each unique item appears in
        values.

    Returns
    -------
    unique : ndarray
        The sorted unique values.

    unique_inverse : ndarray
        The indices to reconstruct the original array from the unique array.
        Only provided if `return_inverse` is True.

    unique_counts : ndarray
        The number of times each of the unique values comes up in the original
        array. Only provided if `return_counts` is True.
    """
    if values.dtype == object:
        return _unique_python(
            values, return_inverse=return_inverse, return_counts=return_counts
        )
    # numerical
    return _unique_np(
        values, return_inverse=return_inverse, return_counts=return_counts
    )


def _unique_np(values, return_inverse=False, return_counts=False):