topic Re: How to get an array from the results of an iteration in Python Questions

How to get an array from the results of an iteration

mlopezr95984 — Tue, 06 Jul 2021 04:58:30 GMT

Hello,

I am trying to generate an array out of the results of this iteration.

import numpy as np

num=3

for x in range(num+1):

a=np.array([2,x])

print(a)

Result:
[2 0]
[2 1]
[2 2]
[2 3]

So, I would like to have an array

a = [2 0 2 1 2 2 2 3]

I have not figured out how to apply a np.concatenate as it does not allow me to assign a variable to each result.

Any ideas?

Thank you!

Re: How to get an array from the results of an iteration

DanPatterson — Tue, 06 Jul 2021 08:02:47 GMT

num=3 lst =[] for x in range(num+1): lst.append([2, x]) out = np.array(lst) out Out[4]: array([[2, 0], [2, 1], [2, 2], [2, 3]]) out.ravel() Out[5]: array([2, 0, 2, 1, 2, 2, 2, 3])

better

num=3 lst =[] for x in range(num+1): lst.extend([2, x]) out = np.array(lst) out Out[7]: array([2, 0, 2, 1, 2, 2, 2, 3])

better

skip iteration all together

num = 4 val = 2 a = np.empty(shape=(num, 2), dtype=np.int32) a.fill(val) a[:, 1] = np.arange(num) a array([[2, 0], [2, 1], [2, 2], [2, 3]]) a.ravel() array([2, 0, 2, 1, 2, 2, 2, 3])

There are more efficient ways.

Also note, create the final array at the end

Re: How to get an array from the results of an iteration

mlopezr95984 — Tue, 06 Jul 2021 12:52:05 GMT

Thank you Dan!