在另一个数组中查找Python数组的索引

Question

假设我有两个Numpy数组：

a = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
b = np.array([7, 8, 9])

如何轻松找到b中a的位置？在这种情况下，我想要2。 numpy.where()会返回有用的信息，但仍需要处理。我已经为此编写了一个函数，如下所示，但必须有一个更简单的方法。

def find_vertical_array_index(a, b):
    """Find array in another array.

    Parameters
    ----------
    a: numpy array
    Array to find array in.
    b: numpy array
         Array to find array. Must have dimensions 1 by n.

    Returns
    -------
    Integer value of index where b first occurs in a.

    Notes
    -----
    Only searches through the array vertically and returns the first index.
    If array does not occur, nothing is returned.

    Examples
    --------
    >>> x = np.array([[5, 3, 1, 1], [9, 9, 9, 8], [9, 3, 7, 9]])
    >>> y = np.array([9, 9, 9, 8])
    >>> find_vertical_array_index(x, y)
    1

    >>> x = np.array([[9, 9, 9, 8], [9, 9, 9, 8], [9, 3, 7, 9]])
    >>> y = np.array([9, 9, 9, 9])
    0
    """
    try:
        index = list(Counter(np.where(a == b)[0]).values()).index(len(b))
    except ValueError:
        pass
    return list(Counter(np.where(a == b)[0]).keys())[index]