Python Membership and Identity Operators | in, not in, is, is not

Membership Operators

Membership operators are operators used to validate the membership of a value. It test for membership in a sequence, such as strings, lists, or tuples.

1. in operator : The ‘in’ operator is used to check if a value exists in a sequence or not. Evaluates to true if it finds a variable in the specified sequence and false otherwise.

   # Python program to illustrate # Finding common member in list  # using 'in' operator list1=[1,2,3,4,5] list2=[6,7,8,9] for item in list1:     if item in list2:         print("overlapping")       else:     print("not overlapping")

   Output:

   not overlapping
   

   Same example without using in operator:

   # Python program to illustrate  # Finding common member in list  # without  using 'in' operator    #  Define a function() that takes two lists def overlapping(list1,list2):         c=0     d=0     for i in list1:         c+=1     for i in list2:         d+=1     for i in range(0,c):         for j in range(0,d):             if(list1[i]==list2[j]):                 return 1      return 0 list1=[1,2,3,4,5] list2=[6,7,8,9] if(overlapping(list1,list2)):     print("overlapping") else:     print("not overlapping")

   Output:

   
   
   

   not overlapping
   

2. ‘not in’ operator- Evaluates to true if it does not finds a variable in the specified sequence and false otherwise.

   # Python program to illustrate # not 'in' operator x = 24 y = 20 list = [10, 20, 30, 40, 50 ];    if ( x not in list ):    print "x is NOT present in given list" else:    print "x is  present in given list"    if ( y in list ):    print "y is present in given list" else:    print "y is NOT present in given list"

Identity operators

In Python are used to determine whether a value is of a certain class or type. They are usually used to determine the type of data a certain variable contains.
There are different identity operators such as

1. ‘is’ operator – Evaluates to true if the variables on either side of the operator point to the same object and false otherwise.

   # Python program to illustrate the use  # of 'is' identity operator x = 5 if (type(x) is int):     print ("true") else:     print ("false")

   Output:

      true
   

2. ‘is not’ operator – Evaluates to false if the variables on either side of the operator point to the same object and true otherwise.

   # Python program to illustrate the  # use of 'is not' identity operator x = 5.2 if (type(x) is not int):     print ("true") else:     print ("false")

   Output:

     true