numpy.ix — NumPy v1.11 Manual (original) (raw)

numpy.ix_(*args)[source]¶

Construct an open mesh from multiple sequences.

This function takes N 1-D sequences and returns N outputs with N dimensions each, such that the shape is 1 in all but one dimension and the dimension with the non-unit shape value cycles through all N dimensions.

Using ix_ one can quickly construct index arrays that will index the cross product. a[np.ix_([1,3],[2,5])] returns the array[[a[1,2] a[1,5]], [a[3,2] a[3,5]]].

Examples

a = np.arange(10).reshape(2, 5) a array([[0, 1, 2, 3, 4], [5, 6, 7, 8, 9]]) ixgrid = np.ix_([0,1], [2,4]) ixgrid (array([[0], [1]]), array([[2, 4]])) ixgrid[0].shape, ixgrid[1].shape ((2, 1), (1, 2)) a[ixgrid] array([[2, 4], [7, 9]])