Matrix of sliding window ngrams without any copying via numpy striding tricks

ngrams_via_striding.py

from numpy.lib.stride_tricks import as_strided
def ngrams_via_striding(array, order):
    itemsize = array.itemsize
    assert array.strides == (itemsize,)
    return as_strided(array, (max(array.size + 1 - order, 0), order), (itemsize, itemsize))

In [71]: a = numpy.arange(10)

In [72]: ngrams_via_striding(a, 4)
Out[72]: 
array([[0, 1, 2, 3],
       [1, 2, 3, 4],
       [2, 3, 4, 5],
       [3, 4, 5, 6],
       [4, 5, 6, 7],
       [5, 6, 7, 8],
       [6, 7, 8, 9]])