Python not in string

Using Python “not in” operator in the string you can check if the string contains another string. Python string supports in operator. The in-operator syntax is:

sub in str

Not in

sub not in str

Python is not in string

Simple example code checks if a string is part of another string or not. It returns false if the “sub” string is part of “str”, otherwise it returns true.

str1 = 'I love Python Programming:'

str2 = 'Python'

str3 = 'Java'

print(f'"{str1}" contains "{str2}" = {str2 not in str1}')
print(f'"{str1}" contains "{str2.lower()}" = {str2.lower() not in str1}')
print(f'"{str1}" contains "{str3}" = {str3 not in str1}')

if str2 in str1:
    print(f'"{str1}" contains "{str2}"')
else:
    print(f'"{str1}" does not contain "{str2}"')

Output:

The simplest and fastest way to check whether a string contains a substring or not in Python is by using the “in” operator, which is used as a comparison operator. Some other Python methods such as find(), index(), count(), etc. also help to Check if a string contains a substring.

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

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.