Python: concatenate 3 arrays

Question

I have its arrays and want to combine them

import numpy as np a = np.array([[1,2,3],[4,5,6]]) b = np.array([[7,8,9],[10,11,12]]) c = np.array([[13,14,15],[16,17,18]]) 

To obtain:

 array([1,2,3,7,8,9,13,14,15, 4,5,6,10,11,12,16,17,18]) 

What is the function for this?

Thanks:)

Answer 1

Stack them horizontally np.hstack and flatten with np.ravel -

 np.hstack(( a,b,c )).ravel() 

Answer 2

 d=np.concatenate((a, b,c), axis=None)