Membership Operators in Python

Types of Python Membership Operators

There are two membership operators in Python.

We use "in" to determine whether an object is present in any sequence and use "not in" to determine whether an object is absent from any sequence.

Return Value: The return value of membership operators are boolean values(TRUE or FALSE).

Let’s see the types of membership operators in detail using some examples.

In and Not In are binary operators, just like many other operators. Thus, two operands can be connected to form expressions. 

Left Operand: The target value you wish to find in the set of values is the left operand.

Right Operand: The set of values where the target value might be found is the right operand.

The syntax of the membership operators in Python is as follows:

item in collection
item not in collection

Examples of Membership Operators

1. in Operator in Python

We will see various examples to understand the working of “in” operators in Python.

Example 1

Here, we will check for the target value in strings, lists, tuples, and sets.

1. Strings

We will check a character in the given string.

Code Implementation:

• Python

Python

print('d' in 'Code_Studio')
print('p' in 'Coding_Ninjas')

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Output:

True
False

Explanation: In the above code, we get True for the first line of code because the in operator encounters the character “d” in the given string. The output for the second line of code is False since it cannot find the occurrence.

2. Lists

We will check a number in the given list.

Code Implementation:

• Python

Python

value = 7
list_num = list(range(1, 10))
print(value in list_num)

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Output:

True

Explanation: In the above code, we are getting a True value for the code because the in operator encounters the target value in the given list.

3. Tuples

We will check for a string in the given tuple.

Code Implementation: 

• Python

Python

tuple=('CodingNinjas', 'is', 'the', 'best', 'platform')
print("CodingNinjas" in tuple)
print("Coding Ninjas Studio" in tuple)

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Output:

True
False

Explanation: In the above code, we get True for the first print statement because the in operator encounters the string “CodingNinjas” in the given tuple. The output for the second print statement is False since it cannot find the occurrence.

4. Sets

We will check for a target value in the given sets.

Code Implementation:

• Python

Python

print('Ninja' in {'CodingNinjas', 'is', 'the','best'})
print(15 in {5, 10, 15, 20, 25})

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Output:

False
True

Explanation: In the above code, we get False for the first line of code because the in operator encounters the target value in the given set. The output for the second line of code is True since it can find the occurrence.

Example 2

We will see an example using in operator to find overlapping (same) values, and then we will eliminate the in operator to understand that in operator reduces the complexity.

Code Implementation:

• Python

Python

listA=[2,4,6,8] 
listB=[5,10,15,20] 
for value in listA: 
    if value in listB: 
        print("overlapping Values")     
else: 
    print("No overlapping values")

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Output:

No overlapping values

Explanation: In the above code, we are getting No overlapping values as output since the value of both the lists are different. The condition for the else statement is executed.

Now, we will update the code by eliminating the “in” operator.

Code Implementation:

• Python

Python

def duplicate(listA,listB): 
 
    x =0
    y =0
    for i in listA: 
        x+=1
    for i in listB: 
        y+=1
    for i in range(0,x): 
        for j in range(0,y): 
            if(listA[i]==listB[j]): 
                return 1
    return 0
    
listA=[2,4,6,8] 
listB=[5,10,15,20] 
if(duplicate(listA,listB)): 
    print("overlapping values") 
else: 
    print("No overlapping values")

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Output:

No overlapping values

Explanation: As we can see when we remove the in operator we need to add two loops(nested loop) for the same code. Hence we can say the complexity of the code is increased.

Check out this article - Swapcase in Python and  Convert String to List Python.

2. not in Operator in Python

Now, we will see an example of not in operator. Compared to the in operator, this operator is the complete opposite.

Example of is not operator

Again, we will check for the target value in string, lists, tuples, and sets using not in operator.

1. Strings

We will check a character in the given string.

Code Implementation:

• Python

Python

print('d' not in 'Code_Studio')
print('p' not in 'Coding_Ninjas')

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Run Code

Output:

False
True

Explanation: In the above code, we get False for the first line of code because the not in operator encounters the character “d” in the given string. The output for the second line of code is True since it cannot find the occurrence.

2. Lists

We will check a number in the given list.

Code Implementation:

• Python

Python

value = 7
list_num = list(range(1, 10))
print(value not in list_num)

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Run Code

Output:

False

Explanation: In the above code, we are getting a False value for the code because the not in operator encounters the target value in the given list.

3. Tuples

We will check for a string in the given tuple.

Code Implementation:

• Python

Python

tuple=('CodingNinjas', 'is', 'the', 'best', 'platform')
print("CodingNinjas" not in tuple)
print("Coding Ninjas Studio" not in tuple)

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Output:

False
True

Explanation: In the above code, we get False for the first print statement because the not in operator encounters the string “CodingNinjas” in the given tuple. The output for the second print statement is True since it cannot find the occurrence.

4. Sets

We will check for a target value in the given sets.

Code Implementation:

• Python

Python

print('Ninja' not in {'CodingNinjas', 'is', 'the','best'})
print(15 not in {5, 10, 15, 20, 25})

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Output:

True
False

Explanation: In the above code, we get True for the first line of code because the not in operator encounters the target value in the given set. The output for the second line of code is False since it can find the occurrence.

Example 2

We will cover another example to see the difference in working of in and not in operators.

Code Implementation:

• Python

Python

a = 4
b = 2
list_num = [3, 4, 5, 6, 7 ]; 
 
if ( a not in list_num ): 
    print ("4 is not present in the given list")
else:
    print ("4 is present in the given list")
 
if ( b in list_num ): 
    print ("2 is present in the given list")
else: 
    print ("2 is not present in the given list")

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Output:

4 is present in the given list
2 is not present in the given list

Identity Operators in Python

In addition to membership operators, Python also supports a different class of operators referred to as identity operators. Python uses identity operators to determine whether a given value belongs to a specific class or type. Identity operators are frequently used to specify the kind of data that a certain variable contains. 

 Python has two distinct identity operators available:

• is operator
• is not operator

1. is Operator

The is operator in Python returns True if both sides have the same kind. If not, False is returned.

Let's examine a Python programme to understand this better.

Example

The following example checks for the integer data type.

Code Implementation:

• Python

Python

a = 3
if (type(a) is int): 
    print ("True") 
else: 
    print ("False")

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Output:

True

Explanation: In the above code, we get True for the code since a is a member of integer class.

2. is not Operator

The is not operator in Python returns False if both sides have the same kind. If not, True is returned. It is the exact opposite of is operator in Python.

Let's examine a Python programme to understand this better.

Example

The following example checks for integer data type using is not operator.

Code Implementation:

• Python

Python

a = "CN"
if (type(a) is not int): 
    print ("True") 
else: 
    print ("False")

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Run Code

Output:

True

Explanation: In the above code, we get True for the code since “a” is not a member of integer class.

Frequently Asked Questions

What are member operators?

Member operators in Python (in and not in) test if a value is present or absent within a sequence like lists, strings, or tuples.

What is the use of “is operator”?

The "is" operator checks if two variables point to the same object in memory, verifying object identity rather than equality of values.

How do you check for membership in Python?

To check for membership in Python, use the in operator to verify if a value exists in a sequence, such as a list or string.

Why is membership operator used in Python?

Membership operators (in and not in) in Python are used to check if a value exists in a sequence (like a list, string, or tuple) or not, simplifying conditional checks.

What is the symbol for the membership operator?

The symbol for the membership operator in Python is "in." It is used to check if a value is present within a sequence or container.

What kinds of membership operators does Python support?

Python supports two types of membership operators. The first one is IN, and the second one is NOT IN. The IN membership operator specifies the value is present in the desired data sequence.  The NOT IN membership operator specifies the value is not present in the sequence. 

What will be the output of the membership operators in Python?

The membership operator determines whether a value is present or absent in a data sequence. Generally, one can use the IN or NOT IN operators. The output of both membership operators is boolean values(TRUE or FALSE).

What distinguishes a membership operator from an identity operator?

A membership operator in Python checks for the presence of a value within a sequence, such as a string, list, tuple, or set. The membership operators include in and not in.

Conclusion

In conclusion, the membership operators in Python are used to confirm any value's membership in a data set. It checks whether the value is present in a sequence, such as strings, lists, or tuples.

In this article, we saw what membership operators are. We also discussed the features and examples of membership operators in Python.

We hope this blog has helped you. We recommend you visit our articles on different topics of Python, such as:

• Logical XOR of two variables in Python
• Reduce function in Python
• Fibonacci Series in Python
• Python String Concatenation