Assigning 2d array in vector of indices

Question

Given 2d array k = np.zeros((M, N)) and list of indices in the range 0, 1 .., M-1 of size N called places = np.random.random_integers(0, M-1, N) how do I assign 1 in each column of k in the places[i] index where i is running index. I would like to achieve that in python compact style and without any loops

Examples:

N = 5, M =3
places= 0, 0, 1, 1, 2

Then:

k = [1, 1, 0, 0, 0
     0, 0, 1, 1, 0
     0, 0, 0, 0, 1]

MaThMaX · Accepted Answer · 2016-06-11 15:24:40Z

1

rslt = np.zeros((M, N))
for i, v in enumerate(places): rslt[v,i]=1

Full code:

import numpy as np
N = 5
M=3
#places = np.random.random_integers(0, M-1, N)
places= 0, 0, 1, 1, 2
rslt = np.zeros((M, N))
for i, v in enumerate(places): rslt[v,i]=1
print(rslt)

Out [34]:
[[ 1.  1.  0.  0.  0.]
 [ 0.  0.  1.  1.  0.]
 [ 0.  0.  0.  0.  1.]]

answered Jun 11, 2016 at 15:24

MaThMaX

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