Numpy Program to add arrays of Shapes (2, 1, 3) and (1, 4, 1) using Broadcasting

Last update on March 26 2025 13:15:51 (UTC/GMT +8 hours)

15. Broadcast Addition for 3D and 1D Arrays

Given two arrays, x of shape (2, 1, 3) and y of shape (1, 4, 1), use broadcasting write a NumPy program to obtain a result of shape (2, 4, 3) through element-wise addition.

Sample Solution:

Python Code:

import numpy as np

# Initialize the array x of shape (2, 1, 3)
x = np.array([[[1, 2, 3]], 
              [[4, 5, 6]]])

# Initialize the array y of shape (1, 4, 1)
y = np.array([[[ 7], [ 8], [ 9], [10]]])

# Perform element-wise addition using broadcasting
result_array = x + y

# Display the result
print(result_array)

Output:

[[[ 8  9 10]
  [ 9 10 11]
  [10 11 12]
  [11 12 13]]

 [[11 12 13]
  [12 13 14]
  [13 14 15]
  [14 15 16]]]

Explanation:

• Importing numpy: We first import the numpy library for array manipulations.
• Initializing arrays: Arrays x of shape (2, 1, 3) and y of shape (1, 4, 1) are initialized.
• Broadcasting and Addition: Element-wise addition is performed using broadcasting, resulting in an array of shape (2, 4, 3).
• Displaying result: The resulting array is printed out.

For more Practice: Solve these Related Problems:

• Given arrays of shapes (2, 1, 3) and (1, 4, 1), write a function that performs element-wise addition to produce a (2, 4, 3) array.
• Implement a solution that uses np.broadcast_to to manually broadcast arrays to the desired shape before adding.
• Create a program that checks the shapes of the input arrays and automatically reshapes them to be broadcast-compatible.
• Test the addition on sample arrays with known values to verify the correctness of the resulting 3D array.

Python-Numpy Code Editor:

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