Question

write a program to take a list from user then arrange list element in reverse order after doubling each element
input-[2,9,18,7,13,4]
output-[8,26,24,36,18,4]​

Answer 1

Answer:

The given program is written in Python.

1. Using user-defined logic.

n=int(input("How many elements for the list?? "))

print("Enter the elements...")

l=[]

for i in range(n):

   l.append(int(input(">> ")))

print("Given List:",l)

for i in range(n):

   l[i]=2*l[i]

l=l[::-1]

print("Modified List:",l)

Explanation:

• Line 1: Ask the user for the number of elements.
• Line 2: Display a message asking the user for giving input.
• Line 3: Create a list.
• Line 4-5: Adds the elements in the list.
• Line 6: Displays the given list.
• Line 7-8: Here, modification takes place. Each element in the list is replaced with twice of that element.
• Line 9: List is reversed using slicing.
• Line 10: Modified list is shown.

2. Using slicing.

n=int(input("How many elements for the list?? "))

print("Enter the elements...")

l=[]

for i in range(n):

   l.append(int(input(">> ")))

print("Given List:",l)

l=[2*i for i in l][::-1]

print("Modified List:",l)

Explanation:

• This is a modified version of the previous approach. Each element is multiplied with 2 and the result is stored in the last and then the list is reversed. All these works are done in one line (Line 7).

Refer to the attachment for output.

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