manipulating elements of a numpy array in python

Question

I have:

in = array([4, 3, 2, 1,
   -3, -2, -1,  0])

How do I subtract the previous element from the next element like this:

out = array([(3-4), (2-3), (1-2),
             (-3-1), (-2-(-3)), (-1-(-2)), (0-1)]
out = array([-1,-1,-1,-4,1,1,-1])

j1-lee · Accepted Answer · 2021-06-23 19:24:26Z

2

You can simply use np.diff():

import numpy as np
arr = np.array([4, 3, 2, 1, -3, -2, -1, 0])
print(np.diff(arr)) # [-1 -1 -1 -4  1  1  1]

np.diff() returns an numpy array you just described: the differences between two adjacent elements.

answered Jun 22, 2021 at 23:57

j1-lee

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