What does the parameter -1 in numpy shape[::-1] mean?

Question

template = cv2.imread('template.jpg',0)
w, h = template.shape[::-1]

cheersmate · Accepted Answer · 2018-11-21T12:29:42.663

2

Here, it has nothing to do with numpy. You are accessing a tuple with [start:end:step] (see this question for more details), using a step of -1 means you reverse the order.

edited Nov 21 '18 at 12:29

answered Nov 21 '18 at 12:26

cheersmate

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If I don't use -1 my code will be `h, w = template.shape[::-1]`? – zinon Nov 21 '18 at 12:27
If it is a 2D matrix, then it would be `h, w = template.shape`. – cheersmate Nov 21 '18 at 12:31

What does the parameter -1 in numpy shape[::-1] mean?

1 Answers1