Python - Swap two numbers
There are two common ways to swap the value of two variables:
- Swap the value of two variables using a temporary variable
- Swap the value of two variables without using temporary variable
Method 1: Swap the value of two variables using a temporary variable
In the below example, the initial value of variables x and y are 10 and 25. A temporary variable called temp is created to store the value of x and then the value of y is assigned to x. Finally, value of temp (which stores values of x) is assigned to variable y. The final value of variables x and y after swap are 25 and 10 respectively.
def swap(x, y): print("Before Swap.") print("x =",x) print("y =",y) #Swap technique temp = x x = y y = temp print("After Swap.") print("x =",x) print("y =",y) swap(10, 25)
The above code will give the following output:
Before Swap. x = 10 y = 25 After Swap. x = 25 y = 10
Method 2: Swap the value of two variables without using temporary variable
+ operator is used to swap the value of two variables. In this method no temporary variable is used. Please see the example below for syntax.
def swap(x, y): print("Before Swap.") print("x =",x) print("y =",y) #Swap technique x = x + y y = x - y x = x - y print("After Swap.") print("x =",x) print("y =",y) swap(10, 25)
The above code will give the following output:
Before Swap. x = 10 y = 25 After Swap. x = 25 y = 10
Similarly, others operators can also be used in this method. Please see the page: Python - Swap two numbers without using Temporary Variable.
Method 3: Swap the value of two variables using = operator
In python, the value of two variables can be swapped using assignment operator also. Please see the example below for syntax.
x = 10 y = 25 print("Before Swap.") print("x =",x) print("y =",y) #Swap technique x , y = y, x print("After Swap.") print("x =",x) print("y =",y)
The above code will give the following output:
Before Swap. x = 10 y = 25 After Swap. x = 25 y = 10