Write the definition of a user defined function PushNV(N) which accepts a list of strings in the parameter N a

Question

Q. Write the definition of a user defined function PushNV(N) which accepts a list of strings in the parameter N and pushes all strings which have no vowels present in it, into a list named NoVowel. Write a program in Python to input 5 words and push them one by one into a list named All. The program should then use the function PushNV() to create a stack of words in the list NoVowel so that it stores only those words which do not have any vowel present in it, from the list All. Thereafter, pop each word from the list NoVowel and display the popped word. When the stack is empty display the message "EmptyStack". For example: If the Words accepted and pushed into the list All are ['DRY', 'LIKE', 'RHYTHM', 'WORK', 'GYM'] Then the stack NoVowel should store ['DRY', 'RHYTHM', 'GYM'] And the output should be displayed as GYM RHYTHM DRY EmptyStack

(OR)

Write the definition of a user defined function Push3_5(N) which accepts a list of integers in a parameter N and pushes all those integers which are divisible by 3 or divisible by 5 from the list N into a list named Only3_5. Write a program in Python to input 5 integers into a list named NUM. The program should then use the function Push3_5() to create the stack of the list Only3_5. Thereafter pop each integer from the list Only3_5 and display the popped value. When the list is empty, display the message "StackEmpty". For example: If the integers input into the list NUM are: [10, 6, 14, 18, 30] Then the stack Only3_5 should store [10, 6, 18, 30] And the output should be displayed as 30 18 6 10 StackEmpty

CBSECBSE Class XII Board 2022Subjective· 3mImportance★★★★★

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Part (a)Concept understanding — List Stack Operations

Let’s begin with something you already know: a stack of plates in a cafeteria. You can only take the top plate off, and you can only put a new plate on top. You never pull a plate from the middle or the bottom. That everyday action is the core idea behind a stack in computer science — a list where all additions and removals happen at one end, called the top.

Now, in your NCERT textbook for Informatics Practices or Computer Science (Class 11 or 12), when you study List Stack Operations, you are learning how to treat a Python list as if it were that stack of plates. A normal list lets you add or remove items from anywhere. But a stack is a restricted list: you can only work with the most recently added item. This restriction is not a weakness — it is a deliberate design that makes certain tasks simple and fast.

The two fundamental operations are:

Push – adding an element to the top of the stack.
Pop – removing the top element from the stack.

There is also a third operation, Peek (or Top), which just looks at the top element without removing it. And you will often check if the stack is empty before trying to pop.

Note

In Python, you can implement a stack using a list. The append() method acts as push, and pop() (with no argument) acts as pop. Python’s list already has these built-in, so you don’t need to write any special code — you just use the list in a disciplined way.

Why does this matter? Because stacks are everywhere in real computing. When you press the Back button in a web browser, it pops the previous page off a stack of visited pages. When you undo an action in a word processor, it pops the last change off a stack of edits. Even the way your computer calls one function from another uses a stack behind the scenes. So learning stack operations is not just about lists — it is about understanding a pattern that appears again and again. …

Part (b)Concept understanding — List Stack Operations

The two fundamental operations are:

Push – adding an element to the top of the stack.
Pop – removing the top element from the stack.

There is also a third operation, Peek (or Top), which just looks at the top element without removing it. And you will often check if the stack is empty before trying to pop.

Note

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Both alternatives use a Python list as a stack: filter items into the stack, then pop and display in LIFO order.

Part (a)

Push only words that contain no vowel into NoVowel, then pop and display.

NoVowel = []
def PushNV(N):
    for word in N:
        if not any(ch in "AEIOUaeiou" for ch in word):
            NoVowel.append(word)

All = []
for i in range(5):
    All.append(input("Enter a word: "))
PushNV(All)
while len(NoVowel) > 0:
    print(NoVowel.pop())
print("EmptyStack")

For ['DRY','LIKE','RHYTHM','WORK','GYM'] the stack is ['DRY','RHYTHM','GYM'] and the output is:

GYM
RHYTHM
DRY
EmptyStack …

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Part (a): push vowel-free words onto a list stack, pop them → GYM RHYTHM DRY EmptyStack. Part (b): push numbers divisible by 3 or 5, pop them → 30 18 6 10 StackEmpty.

A Python list works as a stack: append() pushes onto the top and pop() removes the top (LIFO).

Part (a)

PushNV(N) walks the list of words and keeps those that contain no vowel (checked case-insensitively). The words are pushed in input order, so the last vowel-free word sits on top and pops first.

NoVowel = []
def PushNV(N):
    for word in N:
        if not any(ch in "AEIOUaeiou" for ch in word):
            NoVowel.append(word)

All = []
print("Enter 5 words:")
for i in range(5):
    All.append(input())
PushNV(All)
while len(NoVowel) > 0:
    print(NoVowel.pop())
print("EmptyStack")

With ['DRY','LIKE','RHYTHM','WORK','GYM'], LIKE and WORK contain vowels and are skipped, so NoVowel = ['DRY','RHYTHM','GYM']. Popping the top each time prints:

GYM
RHYTHM
DRY
EmptyStack …

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Same / Similar Concept — real previous-year questions on the same or a closely similar concept, not this exact question.

CBSE 2023Set 91/41 markMCQ
$Q. Q. 17 and 18 are Assertion (A) and Reasoning (R) based questions. Mark the correct choice as$
(a) Both (A) and (R) are true and (R) is the correct explanation for (A).
(b) Both (A) and (R) are true and (R) is not the correct explanation for (A).
(c) (A) is true but (R) is false.
(d) (A) is false but (R) is true. Assertion (A) : In Python, a stack can be implemented using a list. Reasoning (R) : A stack is an ordered linear list of elements that works on the principle of First In First Out (FIFO).
›Reveal solutionSolution

The assertion is true, but the reasoning is false because a stack follows LIFO, not FIFO.

Let’s take this step by step. The Assertion says that in Python, a stack can be implemented using a list. That is perfectly correct. Python’s built-in list type provides methods like append() to add an element at the end and pop() to remove the last element — exactly the operations needed for a stack. Many textbooks and real-world Python code use lists as stacks, so this part is true. …
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Part (a)

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