Divide columns of 2D array by 1D array using NumPy Broadcasting

NumPy: Broadcasting Exercise-6 with Solution

Write a NumPy program that divides each column of a 2D array x of shape (4, 3) by a 1D array y of shape (4,) using broadcasting.

Sample Solution:

Python Code:

# Import the NumPy library
import numpy as np

# Create a 2D array x with shape (4, 3)
x = np.array([[8, 16, 24],
              [2, 4, 6],
              [12, 24, 36],
              [4, 8, 12]])

# Create a 1D array y with shape (4,)
y = np.array([2, 2, 3, 4])

# Reshape y to be a column vector (4, 1) for broadcasting
y_reshaped = y.reshape(4, 1)

# Divide each column of x by y using broadcasting
result = x / y_reshaped

# Print the original arrays and the result
print("2D Array x:\n", x)
print("1D Array y:\n", y)
print("Result of x / y:\n", result)

Output:

2D Array x:
 [[ 8 16 24]
 [ 2  4  6]
 [12 24 36]
 [ 4  8 12]]
1D Array y:
 [2 2 3 4]
Result of x / y:
 [[ 4.  8. 12.]
 [ 1.  2.  3.]
 [ 4.  8. 12.]
 [ 1.  2.  3.]]

Explanation:

• Import the NumPy library: This step imports the NumPy library, essential for numerical operations.
• Create a 2D array x with shape (4, 3): We use np.array to create a 2D array x with the specified shape and elements.
• Create a 1D array y with shape (4,): We use np.array to create a 1D array y with the specified shape and elements.
• Reshape y to be a column vector (4, 1) for broadcasting: We reshape y to make it compatible for broadcasting with x by changing its shape to (4, 1).
• Divide each column of x by y using broadcasting: NumPy automatically applies broadcasting to divide each element in the columns of x by the corresponding element in y.
• Print the original arrays and the result: This step prints the original 2D array x, the 1D array y, and the result of the division.

Python-Numpy Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Element-wise multiplication with reshaped arrays using NumPy.
Next: Numpy program to Transpose and add arrays.