Entering values at specific locations in an array in Python

Question

I have a list T2 and an array X containing numpy arrays of different shape. I want to rearrange values in these arrays according to T2. For example, for X[0], the elements should occupy locations according to T2[0] and 0. should be placed for locations not mentioned. Similarly, for X[1], the elements should occupy locations according to T2[1]. I present the expected output.

import numpy as np

T2 = [[0, 3, 4, 5], [1, 2, 3, 4]]

X=np.array([np.array([4.23056174e+02, 3.39165087e+02, 3.98049092e+02, 3.68757486e+02]),
       np.array([4.23056174e+02, 3.48895801e+02, 3.48895801e+02, 3.92892424e+02])])

The expected output is

X=array([array([4.23056174e+02, 0, 0, 3.39165087e+02, 3.98049092e+02, 3.68757486e+02]),
      array([0, 4.23056174e+02, 3.48895801e+02, 3.48895801e+02, 3.92892424e+02])])

Asked By: AEinstein

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Source

Answer 1

import numpy as np

T2 = ...
X = ...

out = []

for t, x in zip(T2, X):
    temp = np.zeros(max(t) + 1)
    temp[t] = x
    out.append(temp)

out = np.array(out, dtype=object)

out:

array([array([423.056174,   0.      ,   0.      , 339.165087, 398.049092,
              368.757486])                                               ,
       array([  0.      , 423.056174, 348.895801, 348.895801, 392.892424])],
      dtype=object)

Answered By: Chrysophylaxs

Entering values at specific locations in an array in Python

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