NumPy: Find indices of elements equal to zero in a NumPy array
Find Indices of Elements Equal to Zero
Write a NumPy program to find the indices of elements equal to zero in a NumPy array.
Sample Solution:
Python Code:
# Importing the NumPy library and aliasing it as 'np'
import numpy as np
# Creating a NumPy array 'nums' containing integers
nums = np.array([1, 0, 2, 0, 3, 0, 4, 5, 6, 7, 8])
# Printing a message indicating the original array will be displayed
print("Original array:")
# Printing the original array 'nums'
print(nums)
# Finding the indices of elements equal to zero in the array 'nums'
# Using np.where() to find the indices where the elements are equal to 0 and accessing the first (and only) array of indices
result = np.where(nums == 0)[0]
# Printing the indices of elements equal to zero in the array 'nums'
print("Indices of elements equal to zero of the said array:")
print(result)
Sample Output:
Original array: [1 0 2 0 3 0 4 5 6 7 8] Indices of elements equal to zero of the said array: [1 3 5]
Explanation:
In the above code –
nums = np.array([1,0,2,0,3,0,4,5,6,7,8]): Create a NumPy array 'nums' containing the specified integer values.
np.where(nums == 0): Use the np.where() function to find the indices of elements in the 'nums' array that are equal to 0. The expression nums == 0 creates a boolean array of the same shape as 'nums', with True at the positions where the element is 0 and False elsewhere.
np.where(nums == 0)[0]: The np.where() function returns a tuple, but we are only interested in the first element of that tuple (the array of indices). To extract the first element, we use the index [0]. Store the array of indices to the variable 'result'.
print(result): Print the resulting 'result' array.
Pictorial Presentation:
For more Practice: Solve these Related Problems:
- Write a NumPy program to find the indices of zero-valued elements in a 1D array using np.where.
- Create a function that returns the index positions of all zeros in a multi-dimensional array after flattening.
- Test the zero-index finder on an array with sporadic zeros and verify the output against manual indexing.
- Implement a solution that highlights the zero elements in the original array by printing their coordinates.
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