NumPy: Move the specified axis backwards, until it lies in a given position

NumPy: Array Object Exercise-53 with Solution

Write a NumPy program to move the specified axis backwards, until it lies in a given position.
Move the following 3rd array axes to first position.
(2,3,4,5)

Pictorial Presentation:

Sample Solution:

Python Code:

# Importing the NumPy library with an alias 'np'
import numpy as np

# Creating a NumPy array filled with ones of shape (2, 3, 4, 5)
x = np.ones((2, 3, 4, 5))

# Using rollaxis to roll the axis at index 3 (last axis) to index 1
# Printing the shape of the array after rolling the axis from index 3 to index 1
print(np.rollaxis(x, 3, 1).shape) 

Sample Output:

(2, 5, 3, 4)

Explanation:

In the above code -

x = np.ones((2, 3, 4, 5)): This part creates a 4D array x with the given shape (2, 3, 4, 5), filled with ones.

print(np.rollaxis(x, 3, 1).shape): The np.rollaxis() function takes three arguments: the input array, the axis to be rolled, and the axis to be rolled to. In this case, it rolls axis 3 (the fourth axis) to the position of axis 1 (the second axis). As a result, the shape of the new array is (2, 5, 3, 4).

Python-Numpy Code Editor:

Previous: Write a NumPy program to move axes of an array to new positions. Other axes remain in their original order.
Next: Write a NumPy program to convert specified inputs to arrays with at least one dimension.