Module « numpy.matlib »

Fonction intersect1d - module numpy.matlib

Signature de la fonction intersect1d

def intersect1d(ar1, ar2, assume_unique=False, return_indices=False) 

Description

intersect1d.__doc__

    Find the intersection of two arrays.

    Return the sorted, unique values that are in both of the input arrays.

    Parameters
    ----------
    ar1, ar2 : array_like
        Input arrays. Will be flattened if not already 1D.
    assume_unique : bool
        If True, the input arrays are both assumed to be unique, which
        can speed up the calculation.  If True but ``ar1`` or ``ar2`` are not
        unique, incorrect results and out-of-bounds indices could result.
        Default is False.
    return_indices : bool
        If True, the indices which correspond to the intersection of the two
        arrays are returned. The first instance of a value is used if there are
        multiple. Default is False.

        .. versionadded:: 1.15.0

    Returns
    -------
    intersect1d : ndarray
        Sorted 1D array of common and unique elements.
    comm1 : ndarray
        The indices of the first occurrences of the common values in `ar1`.
        Only provided if `return_indices` is True.
    comm2 : ndarray
        The indices of the first occurrences of the common values in `ar2`.
        Only provided if `return_indices` is True.


    See Also
    --------
    numpy.lib.arraysetops : Module with a number of other functions for
                            performing set operations on arrays.

    Examples
    --------
    >>> np.intersect1d([1, 3, 4, 3], [3, 1, 2, 1])
    array([1, 3])

    To intersect more than two arrays, use functools.reduce:

    >>> from functools import reduce
    >>> reduce(np.intersect1d, ([1, 3, 4, 3], [3, 1, 2, 1], [6, 3, 4, 2]))
    array([3])

    To return the indices of the values common to the input arrays
    along with the intersected values:

    >>> x = np.array([1, 1, 2, 3, 4])
    >>> y = np.array([2, 1, 4, 6])
    >>> xy, x_ind, y_ind = np.intersect1d(x, y, return_indices=True)
    >>> x_ind, y_ind
    (array([0, 2, 4]), array([1, 0, 2]))
    >>> xy, x[x_ind], y[y_ind]
    (array([1, 2, 4]), array([1, 2, 4]), array([1, 2, 4]))