NumPy: Test whether a given 2D array has null columns or not
Check if a 2D array has null columns.
Write a NumPy program to test whether a given 2D array has null columns or not.
Pictorial Presentation:
Sample Solution:
Python Code:
# Importing the NumPy library
import numpy as np
# Displaying the message indicating the original array
print("Original array:")
# Generating a random integer array of shape (4, 10) with values ranging from 0 to 2
nums = np.random.randint(0, 3, (4, 10))
# Displaying the original array
print(nums)
# Checking if the array has any null columns and displaying the result
print("\nTest whether the said array has null columns or not:")
print((~nums.any(axis=0)).any())
Sample Output:
Original array: [[1 2 1 1 1 2 1 1 2 0] [1 1 0 0 0 0 2 1 2 0] [0 0 2 1 0 2 2 2 2 2] [1 1 1 2 0 0 0 0 1 2]] Test whether the said array has null columns or not: False
Explanation:
In the above exercise -
nums = np.random.randint(0,3,(4,10)): Generates a 4x10 NumPy array nums with random integers from the range [0, 3).
print((~nums.any(axis=0)).any()):
In the above code -
- nums.any(axis=0): Returns a boolean array of shape (10,) with True at positions where there is at least one non-zero element in the corresponding column of nums, and False otherwise. The axis=0 parameter specifies that the operation should be performed along the columns.
- ~nums.any(axis=0): Inverts the boolean values in the array from step 2 using the bitwise NOT operator ~. Now, True indicates that a column has all zeros, and False indicates that there is at least one non-zero element in the column.
- (~nums.any(axis=0)).any(): Checks if there is at least one True value in the boolean array from step 3, i.e., if there is any column in nums with all zeros.
- print((~nums.any(axis=0)).any()): Finally print() function prints the result from step 4. If it prints True, there is at least one column with all zeros; otherwise, no such column exists.
Python-Numpy Code Editor: