Membership operators in Python

 

Membership operators in Python

Python provides membership operators to test for the presence of a value within a sequence (like strings, lists, tuples, or sets) or the presence of a key within a dictionary. These operators return a Boolean value (True or False).

There are two membership operators in Python:

in operator:

The in operator evaluates to True if the value on its left operand is found within the sequence or collection on its right operand.

Otherwise, it evaluates to False.

Python 

x = ["apple", "banana"]

print("banana" in x)

Output 

True

# returns True because a sequence with the value "banana" is in the list

Not in operator:

The not in operator evaluates to True if the value on its left operand is not found within the sequence or collection on its right operand.

Otherwise, it evaluates to False. This operator essentially provides the opposite result of the in operator.

Python 

x = ["apple", "banana"]

print("pineapple" not in x)

Output

True 

# returns True because a sequence with the value "pineapple" is not in the list