How to compare two NumPy arrays?

Sometimes you need to check if two arrays are same or compare their values. NumPy provides multiple ways to do this from simple equality checks to element-wise comparisons. Comparing arrays helps in:

• Validating data correctness
• Checking results of operations
• Filtering or selecting data based on conditions

Let’s explore different methods to compare two arrays.

Using np.array_equal()

The array_equal() function is the simplest and most reliable way to compare two arrays. It checks whether:

• Both arrays have the same shape
• All elements are exactly the same

Syntax:

numpy.array_equal(arr1, arr2)

Example: This code compares two arrays using np.array_equal() and prints whether they are equal.

import numpy as np

arr1 = np.array([[1, 2], [3, 4]])
arr2 = np.array([[1, 2], [3, 4]])

if np.array_equal(arr1, arr2):
    print("Equal")
else:
    print("Not Equal")

Equal

Explanation: np.array_equal() returns True if arrays have the same elements and shape. It’s the cleanest and most reliable way to check equality.

Using == and .all()

This method first compares arrays element-wise using ==, then checks if all results are True with .all().

Example: This code uses element-wise comparison followed by .all() to decide if two arrays are fully equal.

import numpy as np

arr1 = np.array([[1, 2], [3, 4]])
arr2 = np.array([[1, 2], [3, 4]])

dif = arr1 == arr2
b = dif.all()
print(b)

True

Explanation: Every element matches, so result is True. If even one element was different, it would return False.

Using Comparison Operators (>, <, >=, <=)

This method is not for equality checks, but for comparing values element by element. It helps when you want to know which array elements are greater/smaller.

Example: This code compares two arrays element by element using greater/less operators.

import numpy as np

a = np.array([101, 99, 87])
b = np.array([897, 97, 111])

print("Array a:", a)
print("Array b:", b)

print("a > b:", np.greater(a, b))        
print("a >= b:", np.greater_equal(a, b)) 
print("a < b:", np.less(a, b))           
print("a <= b:", np.less_equal(a, b))     

Array a: [101  99  87]
Array b: [897  97 111]
a > b: [False  True False]
a >= b: [False  True False]
a < b: [ True False  True]
a <= b: [ True False  True]

Explanation: The result is a Boolean array, where each element shows the comparison result at that position. This is useful for conditional checks, not equality.