Function delete

numpy/lib/_function_base_impl.py:5221–5397

Return a new array with sub-arrays along an axis deleted. For a one dimensional array, this returns those entries not returned by `arr[obj]`. Parameters ---------- arr : array_like Input array. obj : slice, int, array-like of ints or bools Indicate indic

(arr, obj, axis=None)

@array_function_dispatch(_delete_dispatcher)
def delete(arr, obj, axis=None):
    """
    Return a new array with sub-arrays along an axis deleted. For a one
    dimensional array, this returns those entries not returned by
    `arr[obj]`.

    Parameters
    ----------
    arr : array_like
        Input array.
    obj : slice, int, array-like of ints or bools
        Indicate indices of sub-arrays to remove along the specified axis.

        .. versionchanged:: 1.19.0
            Boolean indices are now treated as a mask of elements to remove,
            rather than being cast to the integers 0 and 1.

    axis : int, optional
        The axis along which to delete the subarray defined by `obj`.
        If `axis` is None, `obj` is applied to the flattened array.

    Returns
    -------
    out : ndarray
        A copy of `arr` with the elements specified by `obj` removed. Note
        that `delete` does not occur in-place. If `axis` is None, `out` is
        a flattened array.

    See Also
    --------
    insert : Insert elements into an array.
    append : Append elements at the end of an array.

    Notes
    -----
    Often it is preferable to use a boolean mask. For example:

    >>> arr = np.arange(12) + 1
    >>> mask = np.ones(len(arr), dtype=np.bool)
    >>> mask[[0,2,4]] = False
    >>> result = arr[mask,...]

    Is equivalent to ``np.delete(arr, [0,2,4], axis=0)``, but allows further
    use of `mask`.

    Examples
    --------
    >>> import numpy as np
    >>> arr = np.array([[1,2,3,4], [5,6,7,8], [9,10,11,12]])
    >>> arr
    array([[ 1,  2,  3,  4],
           [ 5,  6,  7,  8],
           [ 9, 10, 11, 12]])
    >>> np.delete(arr, 1, 0)
    array([[ 1,  2,  3,  4],
           [ 9, 10, 11, 12]])

    >>> np.delete(arr, np.s_[::2], 1)