Python 3 - Identity Operators Example
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Python built-in function id() returns a unique integer as identity of object. Identity operators compare the memory locations of two objects. There are two Identity operators as explained below
| Operator | Description | Example |
|---|---|---|
| is | Evaluates to true if the variables on either side of the operator point to the same object and false otherwise. | x is y, here is results in 1 if id(x) equals id(y). |
| is not | Evaluates to false if the variables on either side of the operator point to the same object and true otherwise. | x is not y, here is not results in 1 if id(x) is not equal to id(y). |
Example
#!/usr/bin/python3
a = 20
b = 20
print ('Line 1','a=',a,':',id(a), 'b=',b,':',id(b))
if ( a is b ):
print ("Line 2 - a and b have same identity")
else:
print ("Line 2 - a and b do not have same identity")
if ( id(a) == id(b) ):
print ("Line 3 - a and b have same identity")
else:
print ("Line 3 - a and b do not have same identity")
b = 30
print ('Line 4','a=',a,':',id(a), 'b=',b,':',id(b))
if ( a is not b ):
print ("Line 5 - a and b do not have same identity")
else:
print ("Line 5 - a and b have same identity")
When you execute the above program it produces the following result −
Line 1 a= 20 : 1594701888 b= 20 : 1594701888 Line 2 - a and b have same identity Line 3 - a and b have same identity Line 4 a= 20 : 1594701888 b= 30 : 1594702048 Line 5 - a and b do not have same identity