Check List Equality in Python

Check Equality of Lists in Python Using the Equality
==
Operator 
Check Equality of Arrays in Python Using the Equality
==
Operator and thenumpy.all()
Method
In this tutorial, we will look into various methods of checking if the two lists are equal in Python. For the two lists to be equal, each element of the first list should be equal to the second list’s corresponding element. If the two lists have the same elements, but the sequence is not the same, they will not be considered equal or identical lists.
Suppose we have listA = [4,7,2,9,1]
, listA
would be equal to listB
if and only if all elements of listB
are identical to listA
, i.e. listB = [4,7,2,9,1]
. We can check whether the two lists are equal in Python using the belowexplained methods.
Check Equality of Lists in Python Using the Equality ==
Operator
A straightforward way to check the equality of the two lists in Python is by using the equality ==
operator. When the equality ==
is used on the list type in Python, it returns True
if the lists are equal and False
if they are not.
The below example code demonstrates how to use the equality ==
operator to check if the two lists are equal in Python.
a = [4,7,3,5,8]
b = [4,7,3,5,8]
c = [1,7,3,5,2]
print(a == b)
print(a == c)
Output:
True
False
Now, let us look into the scenario where we want to get elementwise results. Suppose we want to check which corresponding elements of the second array are equal and which are not equal.
For this, we first need to convert the lists to NumPy
array using the np.array()
method and then use the equality ==
operator, which will return True
or False
for each element.
The below example code demonstrates how to check if the elements of two lists are equal or not in Python.
import numpy as np
a = [4,7,3,5,8]
b = [4,7,3,5,8]
c = [1,7,3,5,2]
print((np.array(a) == np.array(b)))
print((np.array(a) == np.array(c)))
Output:
[ True True True True True]
[False True True True False]
Check Equality of Arrays in Python Using the Equality ==
Operator and the numpy.all()
Method
In many cases, we use the NumPy
arrays for different tasks. If we use the equality ==
operator to check the equality, we will get the elementwise result, as shown in the above example code.
Therefore, to check the equality of the NumPy
arrays in Python, the numpy.all()
method has to be used to check the arrays’ equality. The np.all()
method returns True
if the elements along the given axis evaluate to True
and returns False
otherwise.
The below example code demonstrates how to check whether the two arrays are equal or not in Python.
import numpy as np
a = np.array([1,6,4,8,3])
b = np.array([1,6,4,8,3])
c = np.array([1,4,8,2,3])
print((a == b).all())
print((a == c).all())
Output:
True
False