Question

I have an array of numbers, a. I have a second array, b, specifying how many times I want to retrieve the corresponding element in a. How can this be achieved? The ordering of the output is not important in this case.

import numpy as np

a = np.arange(5)
b = np.array([1,0,3,2,0])

# desired output = [0,2,2,2,3,3]
# i.e. [a[0], a[2], a[2], a[2], a[3], a[3] ]

Answer 1

Thats exactly what np.arange(5).repeat([1,0,3,2,0]) does.