Python compare two lists of strings | Examples

Python doesn’t have a direct method to compare a list. But there are multiple ways to compare the two lists of strings in python.

The following methods to perform List comparison:

• reduce() and map() functions
• collection.counter() method
• sort() method and == operator
• set() method and == operator
• Custom List Comprehension

Note: The cmp() function doesn’t use in Python 3.x version.

Python compares two lists of strings example

Simple example code with all possible ways.

Use reduce() and map() functions

import functools

list1 = ['A', 'B', 'C']
list2 = ['A', 'D', 'E']


if functools.reduce(lambda x, y: x and y, map(lambda a, b: a == b, list1, list2), True):
    print("Both List are same")
else:
    print("Not same")

Output:

Python collection.counter() method

The counter() function counts the frequency of the items in a list and stores the data as a dictionary in the format <value>:<frequency>.

import collections

list1 = ['A', 'B', 'C']
list2 = ['A', 'D', 'E']

if collections.Counter(list1) == collections.Counter(list2):
    print("Both List are same")
else:
    print("Not the same")

Output: Not the same

Use sort() method and == operator to compare lists

The sorted list and the == operator are used to compare the list, element by element.

list1 = ['A', 'B', 'C']
list2 = ['A', 'C', 'B']

list1.sort()
list2.sort()

if list1 == list2:
    print("Both List are the same")
else:
    print("Not same")

Output: Both List are the same

Python set() method and == operator to compare two lists

The equal == operator is used for comparison of the data items of the list in an element-wise fashion.

list1 = ['A', 'B', 'C']
list2 = ['A', 'C', 'B']

s1 = set(list1)
s2 = set(list2)

if s1 == s2:
    print("Both List are the same")
else:
    print("Not same")

Output: Both List are the same

Use Custom List Comprehension to Compare Two Lists

If the string list same then the list has zero elements.

list1 = ['A', 'B', 'C']
list2 = ['A', 'C', 'B']

res = [x for x in list1 + list2 if x not in list1 or x not in list2]

print(res)

Output: []

Do comment if you have any doubts or suggestions on this Python list topic code.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.