Assignment#4 : Mohammed Abdul Wasay

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]

# Printing value of 4th index item in a given list
list1 = [5, 10, 15, 20, 25, 50, 20]
print(list1[3])

20

# updating an item in a list (index = 3) with a value of 200
list1[3]=200
print(list1)

[5, 10, 15, 200, 25, 50, 20]

1. 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]

list1 = [5, 10, 15, 20, 25, 50, 20]
print(list1)

[5, 10, 15, 20, 25, 50, 20]

list1 = [5, 20, 15, 20, 25, 50, 20]
def check(list1, val):
    n=0     
    # traverse in the list
    for x in list1:
         # compare with all the values
        # with val
        if val == list1[n]:
            list1.pop(n)
        n=n+1

check(list1,20)
print(list1)

[5, 15, 25, 50]

1. 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

list1 = [10, 20, 30, 40]
list2 = [100, 200, 300, 400]
print(list1)
print(list2)

[10, 20, 30, 40]
[100, 200, 300, 400]

list1.sort()
print(list1)
list2.sort(reverse=True)
print(list2)

[10, 20, 30, 40]
[400, 300, 200, 100]