Program to access different columns of a multidimensional Numpy array

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Prerequisite: Numpy module

The following article discusses how we can access different columns of multidimensional Numpy array. Here, we are using Slicing method to obtain the required functionality.

Example 1: (Accessing the First and Last column of Numpy array)

Python3

# Importing Numpy module 
import numpy as np 
  
# Creating a 3x3 Numpy array 
arr = np.array([[11, 20, 3],  
                [89, 5, 66],  
                [71, 88, 39]]) 
  
print("Given Array :") 
print(arr) 
  
# Access the First and Last column of array 
res_arr = arr[:,[0,2]] 
print("\nAccessed Columns :") 
print(res_arr)

Output:

Given Array :
[[11 20 3]
[89 5 66] [71 88 39]]
Accessed Columns :
[[11 3] [89 66] [71 39]]

Example 2: (Accessing the Middle and Last column of Numpy array)

Python3

# Importing Numpy module 
import numpy as np 
  
# Creating a 4x4 Numpy array 
arr = np.array([[1, 20, 3, 1],  
                [40, 5, 66, 7],  
                [70, 88, 9, 11], 
               [80, 100, 50, 77]]) 
  
print("Given Array :") 
print(arr) 
  
# Access the Middle and Last column of array 
res_arr = arr[:,[1,3]] 
print("\nAccessed Columns :") 
print(res_arr)

Output:

Given Array :
[[ 1 20 3 1] [ 40 5 66 7] [ 70 88 9 11] [ 80 100 50 77]]
Accessed Columns :
[[ 20 1] [ 5 7] [ 88 11]
[100 77]]

Example 3: (Accessing the Last two columns of Numpy array)

Python3

# Importing Numpy module 
import numpy as np 
  
# Creating a 3d (3X4X4) Numpy array 
arr = np.array([[[21, 20, 3, 1],  
                [40, 5, 66, 7],  
                [70, 88, 9, 11], 
               [80, 100, 50, 77]], 
  
               [[65, 120, 53, 73],  
                [49, 50, 56, 11],  
                [81, 88, 34, 22], 
               [564,56, 76, 99]], 
                 
               [[45, 85, 38, 455],  
                [40, 53, 69, 6],  
                [50, 528, 654, 11], 
               [54, 87, 78, 77]]]) 
  
print("Given Array :") 
print(arr) 
  
# Access the Last two columns of array 
res_arr = arr[2,:,[2,3]] 
print("\nAccessed Columns :") 
print(res_arr)

Output:

Given Array :
[[[ 21 20 3 1]
[ 40 5 66 7]
[ 70 88 9 11]
[ 80 100 50 77]] [[ 65 120 53 73]
[ 49 50 56 11]

[ 81 88 34 22]
[564 56 76 99]] [[ 45 85 38 455]
[ 40 53 69 6]
[ 50 528 654 11]
[ 54 87 78 77]]]
Accessed Columns :
[[ 38 69 654 78] [455 6 11 77]]

Example 4: (Accessing the First column of a 4D Numpy array)

Python3

# Importing Numpy module 
import numpy as np 
  
# Creating a 4D Numpy array 
arr = np.array([ 
  [ 
    [ 
      [1,2], 
      [3,4] 
    ], 
    [ 
      [5,6], 
      [7,8] 
    ] 
  ], 
   [ 
    [ 
      [9,10], 
      [11,12] 
    ], 
    [ 
      [13,14], 
      [15,16] 
    ] 
  ] 
  
]) 
  
print("Given Array :") 
print(arr) 
  
# Access the First three columns of array 
res_arr = arr[0,0,:,[0]] 
print("\nAccessed Columns :") 
print(res_arr)