# numpy.column_stack() in Python

• Last Updated : 06 Jan, 2019

numpy.column_stack() function is used to stack 1-D arrays as columns into a 2-D array.It takes a sequence of 1-D arrays and stack them as columns to make a single 2-D array. 2-D arrays are stacked as-is, just like with hstack function.

Syntax : numpy.column_stack(tup)

Parameters :
tup : [sequence of ndarrays] Tuple containing arrays to be stacked. The arrays must have the same first dimension.
Return : [stacked 2-D array] The stacked 2-D array of the input arrays.

Code #1 :

 # Python program explaining# column_stack() function  import numpy as geek  # input arrayin_arr1 = geek.array(( 1, 2, 3 ))print ("1st Input array : \n", in_arr1)   in_arr2 = geek.array(( 4, 5, 6 ))print ("2nd Input array : \n", in_arr2)   # Stacking the two arrays out_arr = geek.column_stack((in_arr1, in_arr2))print ("Output stacked array:\n ", out_arr)
Output:
1st Input array :
[1 2 3]
2nd Input array :
[4 5 6]
Output stacked array:
[[1 4]
[2 5]
[3 6]]

Code #2 :

 # Python program explaining# column_stack() function  import numpy as geek  # input arrayin_arr1 = geek.array([[ 1, 2, 3], [ -1, -2, -3]] )print ("1st Input array : \n", in_arr1)   in_arr2 = geek.array([[ 4, 5, 6], [ -4, -5, -6]] )print ("2nd Input array : \n", in_arr2)   # Stacking the two arrays out_arr = geek.column_stack((in_arr1, in_arr2))print ("Output stacked array :\n ", out_arr)
Output:
1st Input array :
[[ 1  2  3]
[-1 -2 -3]]
2nd Input array :
[[ 4  5  6]
[-4 -5 -6]]
Output stacked array :
[[ 1  2  3  4  5  6]
[-1 -2 -3 -4 -5 -6]]

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