NumPy: Remove a specific column from a given array

Last update on March 24 2025 13:38:27 (UTC/GMT +8 hours)

Remove specific columns from a 2D array.

Write a NumPy program to remove a specific column from a given array.

Sample Solution:

Python Code:

# Importing NumPy library
import numpy as np

# Generating a random array of shape (7, 5)
nums = np.random.random((7, 5))

# Displaying the original array
print("Original array:")
print(nums)

# Deleting the first column of the array and displaying the updated array
print("\nDelete the first column of the said array:")
print(np.delete(nums, [0], axis=1))

# Deleting the last column of the array and displaying the updated array
print("\nDelete the last column of the said array:")
print(np.delete(nums, [4], axis=1))

Sample Output:

Original array:
[[0.54420704 0.35710194 0.79167579 0.72249474 0.99968936]
 [0.22306352 0.31085825 0.09849254 0.11708716 0.45757945]
 [0.19381592 0.13587749 0.90455038 0.95146017 0.55716851]
 [0.62031347 0.84275698 0.84665943 0.06562172 0.58415968]
 [0.41903059 0.0660559  0.85270403 0.94184265 0.95371587]
 [0.02577681 0.91577282 0.1969686  0.3472482  0.23337827]
 [0.43563908 0.62308811 0.09606371 0.79053989 0.69382428]]

Delete the first column of the said array:
[[0.35710194 0.79167579 0.72249474 0.99968936]
 [0.31085825 0.09849254 0.11708716 0.45757945]
 [0.13587749 0.90455038 0.95146017 0.55716851]
 [0.84275698 0.84665943 0.06562172 0.58415968]
 [0.0660559  0.85270403 0.94184265 0.95371587]
 [0.91577282 0.1969686  0.3472482  0.23337827]
 [0.62308811 0.09606371 0.79053989 0.69382428]]

Delete the last column of the said array:
[[0.54420704 0.35710194 0.79167579 0.72249474]
 [0.22306352 0.31085825 0.09849254 0.11708716]
 [0.19381592 0.13587749 0.90455038 0.95146017]
 [0.62031347 0.84275698 0.84665943 0.06562172]
 [0.41903059 0.0660559  0.85270403 0.94184265]
 [0.02577681 0.91577282 0.1969686  0.3472482 ]
 [0.43563908 0.62308811 0.09606371 0.79053989]]

Explanation:

In the above code -

nums = np.random.random((7, 5)): Creates a 7x5 NumPy array with random numbers between 0 and 1.

print(np.delete(nums, [0], axis=1)) Deletes the first column (index 0) of the nums array along axis 1 (columns) and prints the resulting array.

print(np.delete(nums, [4], axis=1)) Deletes the fifth column (index 4) of the nums array along axis 1 (columns) and prints the resulting array.

For more Practice: Solve these Related Problems:

• Write a NumPy program to remove a column at a given index using np.delete and verify the new shape.
• Create a function that accepts a list of column indices to be removed from a 2D array and returns the resulting array.
• Implement a solution using boolean indexing to filter out columns where the sum is below a specified threshold.
• Test the column removal on arrays with mixed data types to ensure the function handles different dtypes correctly.

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