How to reshape a 2D NumPy array to a 3D array?

Last update on March 26 2025 13:14:47 (UTC/GMT +8 hours)

7. 2D to 3D Array Reshape

Write a NumPy program that creates a 2D array of shape (6, 2) and use reshape() to change it into a 3D array of shape (2, 3, 2). Print the new array.

Sample Solution:

Python Code:

import numpy as np

# Create a 2D array of shape (6, 2)
array_2d = np.array([[1, 2],
                     [3, 4],
                     [5, 6],
                     [7, 8],
                     [9, 10],
                     [11, 12]])

# Use reshape() to change the shape to (2, 3, 2)
array_3d = array_2d.reshape(2, 3, 2)

# Print the new 3D array
print(array_3d)

Output:

[[[ 1  2]
  [ 3  4]
  [ 5  6]]

 [[ 7  8]
  [ 9 10]
  [11 12]]]

Explanation:

• Import NumPy library: We start by importing the NumPy library to work with arrays.
• Create a 2D array: We create a 2D array array_2d of shape (6, 2) using np.array().
• Reshape to (2, 3, 2): We use the reshape() method to change the shape of array_2d to (2, 3, 2), resulting in array_3d.
• Print the result: Finally, we print the new 3D array array_3d.

For more Practice: Solve these Related Problems:

• Write a NumPy program to reshape a 2D array into a 3D array with two different valid shapes and compare their strides.
• Write a NumPy program to reshape a 2D array into a 3D array and then back into 2D, verifying that the original order is preserved.
• Write a NumPy program to reshape a 2D array into a 3D array and check if the total number of elements remains constant.
• Write a NumPy program to attempt an invalid reshape on a 2D array and gracefully handle the resulting error.

Python-Numpy Code Editor:

Previous: How to reshape a 1D NumPy array to multiple dimensions?
Next: How to flatten a 3D NumPy array and print its Strides?