Order sorting of an ndarray by indexes in python?

Question

want to sort np.ndarray indexes of an array such as

[[.5,.7, .9], [.6, .0, .8]]

result would look like this

[[1,1],[0,1],[1,0],[0,1],[1,2],[0,3]]

applying those indexes will get correct sorting order and at same time can be applied to other structures that match the data.

I tried np.argsort, but that doesn't give indexes for ndarray

Carlos Horn · Accepted Answer · 2022-02-22 21:29:25Z

1

You can use np.argsort on the flat array and then use np.divmod to get the indexes of your previous shape. Edit: np.unravel_index is the divmod alternative for higher dimensions, see https://numpy.org/doc/stable/reference/generated/numpy.unravel_index.html

answered Feb 22, 2022 at 21:18

Carlos Horn

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2 Comments

I did zip(*np.unravel_index(np.argsort(arr, axis=None), arr.shape)) to get that output. Thank you

You could also cast the unraveled output to an array and use the transpose instead of zipping.