Assignment – 4

1. You have given a Python list. Write a program to find value 20 in the list, and if it is present, replace it with 200. Only update the first occurrence of an item.
Given input : list1 = [5, 10, 15, 20, 25, 50, 20]
Expected output: [5, 10, 15, 200, 25, 50, 20]

Ans:-
Input_List = [5,10,15,20,25,50,20]
print("Input List : ",Input_List)
first_occurance_Index  = Input_List.index(20)
Input_List[first_occurance_Index] = 200
print("Updated List : ",Input_List)

Output:-
========
   
Input List :  [5, 10, 15, 20, 25, 50, 20]
Updated List :  [5, 10, 15, 200, 25, 50, 20]
                                   =======================================================
2. Given a Python list, write a program to remove all 
occurrences of item 20.

Given input : list1 = [5, 20, 15, 20, 25, 50, 20]

Expected output:[5, 15, 25, 50]

Ans:-
=====
Input_List = [5,10,15,20,25,50,20]
print("Input List : ",Input_List)
try:
        while True:
            Input_List.remove(20)
except ValueError:
        pass
print("Updated List : ",Input_List)
  
Output:-
=======   
Input List :  [5, 10, 15, 20, 25, 50, 20]
Updated List :  [5, 10, 15, 25, 50]

				 ============================================================


3. Given a two Python list. Write a program to iterate both lists simultaneously and display items from list1 in original order and items from list2 in reverse order.

Given input : 
list1 = [10, 20, 30, 40]
list2 = [100, 200, 300, 400]

Expected output:
10 400
20 300
30 200
40 100

Ans:-
=====
list1 = [10, 20, 30, 40]
list2 = [100, 200, 300, 400]
list2.sort(reverse = True)
for i in range(len(list1)):
     print(str(list1[i])+" "+str(list2[i]))

OutPut:-
=======   
10 400
20 300
30 200
40 100