Python Program to Swap Two Elements in a List

Python swap elements in list; Through this tutorial, i am going to show you how to swap elements, two elements and first and last element in list python.

Python Program to Swap Elements in List

  • Python Program to Swap Two Elements in a List using Function.
  • Python Program to Swap the First and Last Value of a List.
  • Python Program to Swap Two Elements in a List using Inbuilt POP() and Insert() Function.

Python Program to Swap Two Elements in a List using Function

  • To declare a number list in program.
  • Take the number of elements in the list and store it in a variable.
  • Iterate for loop to take value one by one and insert them into the list using append() method.
  • Accept input values, which user want to swap in list.
  • Define function and use this formula list[pos1], list[pos2] = list[pos2], list[pos1] to swap value
  • Call function and print result.
# Python Program to Swap Two Elements in a List using Function
     
NumList = []
#how many elements in list
Number = int(input("How many elements in list :- "))
    
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element :- " %i))
    NumList.append(value)
#print list before swapping
print("\nList before swapping of elements :-\n",NumList)
#take position to swap
position1 = int(input("Enter the position 1 of element, which you want to swap :- "))
position2 = int(input("Enter the position 1 of element, which you want to swap :- "))
# Swap function 
def swapPositions(list, pos1, pos2): 
      
    list[pos1], list[pos2] = list[pos2], list[pos1] 
    return list
  
print("List after swapping of elements :-\n",swapPositions(NumList, position1-1, position2-1)) 

After executing the program, the output will be:

How many elements in list :-  6
Please enter the Value of 1 Element :-  1
Please enter the Value of 2 Element :-  2
Please enter the Value of 3 Element :-  3
Please enter the Value of 4 Element :-  4
Please enter the Value of 5 Element :-  5
Please enter the Value of 6 Element :-  6

List before swapping of elements :-
 [1, 2, 3, 4, 5, 6]
Enter the position 1 of element, which you want to swap :-  3
Enter the position 1 of element, which you want to swap :-  6
List after swapping of elements :-
 [1, 2, 6, 4, 5, 3]

2: Python Program to Swap the First and Last Value of a List

  • Declare a number list in program.
  • Take the number of elements in the list and store it in a variable.
  • Iterate for loop to take value one by one and insert them into the list using append() method.
  • Next, swap first and the last element in the list.
  • Print the result.
# Python Program to Swap the First and Last Value of a List
     
NumList = []
#how many elements in list
Number = int(input("How many elements in list :- "))
    
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element :- " %i))
    NumList.append(value)
#print list before swapping
print("\nList before swapping of elements :-\n",NumList)
# Swap list 
temp=NumList[0]
NumList[0]=NumList[Number-1]
NumList[Number-1]=temp
  
print("List after swapping of elements :-\n",NumList) 

After executing the program, the output will be:

How many elements in list :-  5
Please enter the Value of 1 Element :-  5
Please enter the Value of 2 Element :-  4
Please enter the Value of 3 Element :-  3
Please enter the Value of 4 Element :-  2
Please enter the Value of 5 Element :-  1

List before swapping of elements :-
 [5, 4, 3, 2, 1]
List after swapping of elements :-
 [1, 4, 3, 2, 5]

3: Python Program to Swap Two Elements in a List using Inbuilt POP() and Insert() Function.

  • First of all, declare a number list.
  • Take the number of elements in the list and store it in a variable.
  • Iterate for loop to take value one by one and insert them into the list using append() method.
  • Accept input values from user, which user want to swap in list.
  • Define function and use list.pop(pos1) and list.insert(post2) to swap value
  • Call function and print result.
# Python Program to Swap the First and Last Value of a List
     
NumList = []
#how many elements in list
Number = int(input("How many elements in list :- "))
    
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element :- " %i))
    NumList.append(value)
#print list before swapping
print("\nList before swapping of elements :-\n",NumList)
#take position to swap
position1 = int(input("Enter the position 1 of element, which you want to swap :- "))
position2 = int(input("Enter the position 1 of element, which you want to swap :- "))
# Swap function
def swapList(list, pos1, pos2): 
      
    # popping both the elements from list 
    x = list.pop(pos1)    
    y = list.pop(pos2-1) 
     
    # inserting in each others positions 
    list.insert(pos1, y)   
    list.insert(pos2, x)   
      
    return list
 
print("List after swapping of elements :-\n",swapList(NumList, position1-1, position2-1)) 

After executing the program, the output will be:

How many elements in list :-  4
Please enter the Value of 1 Element :-  1
Please enter the Value of 2 Element :-  2
Please enter the Value of 3 Element :-  3
Please enter the Value of 4 Element :-  4

List before swapping of elements :-
[1, 2, 3, 4]
Enter the position 1 of element, which you want to swap :-  2
Enter the position 1 of element, which you want to swap :-  3
List after swapping of elements :-
[1, 3, 2, 4]

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