Q.Write a functions EOReplace() in Python, which accepts a list L of numbers. Thereafter, it increments all even numbers by 1 and decrements all odd numbers by 1. Example: If Sample Input data of the list is: L=(10,20,30,40,35,55) Output will be: L=(11,21,31,41,34,54)

The key idea is conditional modification of list elements during iteration.

The function walks through the list L by index. For each number it checks the parity with the modulo operator: an even number (L[i] % 2 == 0) is incremented by 1, and an odd number is decremented by 1. The list is mutable, so it is changed in place.

def EOReplace(L):
    for i in range(len(L)):
        if L[i] % 2 == 0:
            L[i] = L[i] + 1
        else:
            L[i] = L[i] - 1
``` …

Concept

The task is a straightforward "modify each element by a rule" problem, a common pattern in CBSE Class 12 Computer Science list programs.

• An even number leaves no remainder when divided by 2: n % 2 == 0.
• An odd number leaves a remainder of 1: n % 2 != 0.

To change the elements of the original list in place, we iterate by index using range(len(L)) so that we can assign back to L[i].

The function

def EOReplace(L):
    for i in range(len(L)):
        if L[i] % 2 == 0:      # even number
            L[i] = L[i] + 1
        else:                  # odd number
            L[i] = L[i] - 1

Dry run for L = [10, 20, 30, 40, 35, 55]