Python Membership Operators (Use, Syntax, and Examples)

Python Membership Operators with their usages, syntaxes, and Examples. By IncludeHelp Last updated : December 18, 2023

Python Membership Operators

Python Membership Operators are the operators, which are used to check whether a value/variable exists in the sequences like string, list, tuples, sets, dictionary or not.

These operator returns either True or False, if a value/variable found in the list, its returns True otherwise it returns False.

Python Membership Operators: in, not in

Operator	Description	Example
in	It returns True, if a variable/value found in the sequence.	10 in list1
not in	It returns True, if a variable/value does not found in the sequence.	10 not in list1

1. Python 'in' Operator

The "in" operator returns True, if a variable/value found in the sequence.

Syntax

Below is the syntax of "in" operator:

10 in list1

Python 'in' Operator Example

# Python example of "in" operator

# declare a list and a string
str1 = "Hello world"
list1 = [10, 20, 30, 40, 50]

# Check 'w' (capital exists in the str1 or not
if "w" in str1:
    print("Yes! w found in ", str1)
else:
    print("No! w does not  found in ", str1)

# check 30 exists in the list1 or not
if 30 in list1:
    print("Yes! 30 found in ", list1)
else:
    print("No! 30 does not found in ", list1)

Output

Yes! w found in  Hello world
Yes! 30 found in  [10, 20, 30, 40, 50]

2. Python 'not in' Operator

The "not in" operator returns True, if a variable/value does not found in the sequence.

Syntax

Below is the syntax of "not in" operator:

10 not in list1

Python 'not in' Operator Example

# Python example of "not in" operator

# declare a list and a string
str1 = "Hello world"
list1 = [10, 20, 30, 40, 50]

# check 'X' (capital) exists in the str1 or not
if "X" not in str1:
    print("yes! X does not exist in ", str1)
else:
    print("No!  X exists in ", str1)

# check 90 exists in the list1 or not
if 90 not in list1:
    print("Yes! 90 does not exist in ", list1)
else:
    print("No! 90 exists in ", list1)

Output

yes! X does not exist in  Hello world
Yes! 90 does not exist in  [10, 20, 30, 40, 50]

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