Question

Read a list of n elements. Pass this list to a function which reverses this list in-place without creating a new list.

Answer 1

Answer:

Python provides us with various ways of reversing a list. We will go through few of the many techniques on how a list in python can be reversed.

Examples:

Input : list = [10, 11, 12, 13, 14, 15] Output : [15, 14, 13, 12, 11, 10] Input : list = [4, 5, 6, 7, 8, 9] Output : [9, 8, 7, 6, 5, 4]

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Method 1: Using the reversed() built-in function.

In this method, we neither reverse a list in-place(modify the original list), nor we create any copy of the list. Instead, we get a reverse iterator which we use to cycle through the list.

# Reversing a list using reversed()

def Reverse(lst):

    return [ele for ele in reversed(lst)]

      

# Driver Code

lst = [10, 11, 12, 13, 14, 15]

print(Reverse(lst))

Output:

[15, 14, 13, 12, 11, 10]

Method 2: Using the reverse() built-in function.

Using the reverse() method we can reverse the contents of the list object in-place i.e., we don’t need to create a new list instead we just copy the existing elements to the original list in reverse order. This method directly modifies the original list.

# Reversing a list using reverse()

def Reverse(lst):

    lst.reverse()

    return lst

      

lst = [

Answer 2

Answer:

L=[]

n=int(input("Enter number of values"))

for i in range(n):

   item=int(input("Enter value"))

   L.append(item)

print(L)

L.reverse()

print("Reversed list will be:",L)

Explanation:

Hope this helps!!:D