Given a numpy array, the task is to check whether the numpy array contains all zeroes or not. Let’s discuss few ways to solve the above task. Method #1: Getting count of Zeros using numpy.count_nonzero()
Python3
# Python code to demonstrate# to count the number of elements# in numpy which are zeroimport numpy as npini_array1 = np.array([1, 2, 3, 4, 5, 6, 0])ini_array2 = np.array([0, 0, 0, 0, 0, 0])# printing initial arraysprint("initial arrays", ini_array1)print(ini_array2)# code to find whether all elements are zerocountzero_in1 = np.count_nonzero(ini_array1)countzero_in2 = np.count_nonzero(ini_array2)# printing resultprint("Number of non-zeroes in array1 : ", countzero_in1)print("Number of non-zeroes in array2 : ", countzero_in2) |
Output:
initial arrays [1 2 3 4 5 6 0] [0 0 0 0 0 0] Number of non-zeroes in array1 : 6 Number of non-zeroes in array2 : 0
Time complexity: O(n)
The count_nonzero() function iterates through the entire input array to count the number of non-zero elements.
Auxiliary space complexity: O(1)
The code only uses a constant amount of extra space to store the input arrays and the count of non-zero elements.
Method #2: Using numpy.any()
Python3
# Python code to check that whether# all elements in numpy are zeroimport numpy as npini_array1 = np.array([1, 2, 3, 4, 5, 6, 0])ini_array2 = np.array([0, 0, 0, 0, 0, 0])# printing initial arraysprint("initial arrays", ini_array1)# code to find whether all elements are zerocountzero_in1 = not np.any(ini_array1)countzero_in2 = not np.any(ini_array2)# printing resultprint("Whole array contains zeroes in array1 ?: ", countzero_in1)print("Whole array contains zeroes in array2 ?: ", countzero_in2) |
Output:
initial arrays [1 2 3 4 5 6 0] Whole array contains zeroes in array1 ?: False Whole array contains zeroes in array2 ?: True
Method #3: Using numpy.count_nonzero
Check if all values in array are zero using np.count_nonzero()
Python3
import numpy as np# Initialize the numpy arraysarray1 = np.array([1, 2, 3, 4, 5, 6, 0])array2 = np.array([0, 0, 0, 0, 0, 0])# Check if all values in array1 are zeroif np.count_nonzero(array1) == 0: print("Array 1: all values are zero? True")else: print("Array 1: all values are zero? False")# Check if all values in array2 are zeroif np.count_nonzero(array2) == 0: print("Array 2: all values are zero? True")else: print("Array 2: all values are zero? False")#This code is contributed by Edula Vinay Kumar Reddy |
This will give output as:
Array 1: all values are zero? False
Array 2: all values are zero? True
