Given variables n1 and n2. The mission is to switch the values of each the variables with out the use of 1/3 variable.

Examples: 

X : 10
Y : 20
 
After swapping X and Y, we get :

X : 20
Y : 10

 A :  'Hello'
 B :  'World'
  
After swapping A and B, we get : 

 A :  'World'
 B :  'Hello'

Method 1 :- Using simple built-in method 

left , right = right , left 

This method works for any data type values like string, int, float and is easy to use. 

# Python code to swap two numbers
# without using another variable


x = 5
y = 7

print ("Before swapping: ")
print("Value of x : ", x, " and y : ", y)

# code to swap 'x' and 'y'
x, y = y, x

print ("After swapping: ")
print("Value of x : ", x, " and y : ", y)

Output: 

Before swapping: 
Value of x :  5  and y :  7
After swapping: 
Value of x :  7  and y :  5    

Method 2 :- Using Bitwise XOR operator 

x ^= y
y ^= x
x ^= y

This method only works for integers and works faster because this method uses bit operation (for same values, output = 0 and for different values, output = 1) .

# Python code to swap two numbers
# using Bitwise XOR method


x = 5 # x = 0101
y = 10 # y = 1010

print ("Before swapping: ")
print("Value of x : ", x, " and y : ", y)

# Swap code
x ^= y # x = 1111, y = 1010
y ^= x # y = 0101, x = 1111
x ^= y # x = 1010, y = 0101

print ("After swapping: ")
print("Value of x : ", x, " and y : ", y)

Output: 

Before swapping: 
Value of x :  5  and y :  10
After swapping: 
Value of x :  10  and y :  5

Method 3 :- Using Addition and Subtraction Operators 

x = x + y 
y = x - y
x = x - y

This method works for variables that have numeric values.

# Python code to swap two numbers
# using + and - operators


x = 5.4
y = 10.3

print ("Before swapping: ")
print("Value of x : ", x, " and y : ", y)

# Swap code
x = x + y # x = 15.7, y = 10.3
y = x - y # x = 15.7, y = 5.4
x = x - y # x = 10.3, y = 5.4

print ("After swapping: ")
print("Value of x : ", x, " and y : ", y)

Output: 

Before swapping: 
Value of x :  5.4  and y :  10.3
After swapping: 
Value of x :  10.3  and y :  5.4

Method 4 :- Using Division and Multiplication Operators 

x = x * y
y = x / y
x = x / y

This method works for variables that have numeric values other than 0 .

# Python code to swap two numbers
# using / and * operators


x = 5.4
y = 10.3

print ("Before swapping: ")
print("Value of x : ", x, " and y : ", y)

# Swap code
x = x * y # x = 55.62, y = 10.3
y = x / y # x = 55.62, y = 5.4
x = x / y # x = 10.3, y = 5.4

print ("After swapping: ")
print("Value of x : ", x, " and y : ", y)

Output: 

Before swapping: 
Value of x :  5.4  and y :  10.3
After swapping: 
Value of x :  10.3  and y :  5.4

Method 4: Using both bitwise operators and arithmetic operators:

# python program to swap two numbers
# using bitwise addition for swapping



x = 5;
y = 10;

print ("Before swapping: ") ;
print("Value of x : ", x, " and y : ", y) ;

# same as x = x + y
x = (x & y) + (x|y) ;

#vsame as y = x - y
y = x + (~y) + 1 ;

# same as x = x - y
x = x + (~y) + 1 ;

print ("After swapping: ")
print("Value of x : ", x, " and y : ", y)

# This code is contributed by bunnyram19

Output:

Before swapping: 
Value of x :  5  and y :  10
After swapping: 
Value of x :  10  and y :  5