Python numpy array concatenation

Question

I have a doubt in numpy array concatenation.

For eg,

If I have

a = [ 1, 2, 3]
b = [4, 5, 6, 7]
c= [5, 2]

Could I concatenate arrays of different size??? If so, How could it be possible?

When you say "concatenate", do you mean you want the result to be `[1, 2, 3, 4, 5, 6, 7, 5, 2]`, or do you want to create something like a [jagged array](https://en.wikipedia.org/wiki/Jagged_array) using `a`, `b` and `c` for the rows (so the rows have different lengths)? It would help if you could put that information in the question. — Warren Weckesser, Jan 12 '17 at 09:31
@WarrenWeckesser, No, I want the result to be: [1,2,3,\n,4,5,6,7\n,5,2] — Dhara, Jan 12 '17 at 10:18
Please add that, along with your comment to Ruhul Amin's answer, to the question. — Warren Weckesser, Jan 12 '17 at 10:28

score 1 · Answer 1 · answered Jan 12 '17 at 08:18

1

Yes, You can using numpy.concatenate

import numpy as np
a = [ 1, 2, 3]
b = [4, 5, 6, 7]
c= [5, 2]
d = np.concatenate((a, b, c))

answered Jan 12 '17 at 08:18

Ruhul Amin

My problem is: I want to merge numpy array as a csv file. I used : np.savetxt("output-1.csv", final_array, fmt="%3.2f"). Since"final_array" contains rows of different sizes, it doesnot works – Dhara Jan 12 '17 at 08:53
I want the result to be: [1,2,3,\n,4,5,6,7\n,5,2] – Dhara Jan 12 '17 at 10:43

1 Answers1