Peek Top Element of Stack in DSA Python - Build from Scratch

Peek Top Element of Stack

📖 Scenario: You are managing a stack of books. You want to see which book is currently on the top without removing it.

🎯 Goal: Build a simple stack using a list and write code to peek (look at) the top element of the stack.

📋 What You'll Learn

Create a list called stack with exact elements 'Math', 'Science', 'History'

Create a variable called top_index to hold the index of the top element

Use top_index to get the top element from stack and store it in top_element

Print the value of top_element

💡 Why This Matters

🌍 Real World

Stacks are used in many places like undo features in apps, browser history, and managing tasks in order.

💼 Career

Understanding stacks helps in software development roles where managing data order and temporary storage is needed.

1

Create the stack

Create a list called stack with these exact elements in order: 'Math', 'Science', 'History'

DSA Python

# Create the stack list with the given books
# Your code here

Hint

Use square brackets [] to create a list and separate elements with commas.

2

Find the top index

Create a variable called top_index and set it to the index of the last element in stack using len(stack) - 1

DSA Python

stack = ['Math', 'Science', 'History']
# Create top_index to hold the last element's index
# Your code here

Hint

The last element's index is always the length of the list minus one.

3

Peek the top element

Create a variable called top_element and set it to the element at top_index in stack

DSA Python

stack = ['Math', 'Science', 'History']
top_index = len(stack) - 1
# Get the top element from stack using top_index
# Your code here

Hint

Use square brackets with the index to get an element from a list.

4

Print the top element

Print the value of top_element to show the book on top of the stack

DSA Python

stack = ['Math', 'Science', 'History']
top_index = len(stack) - 1
top_element = stack[top_index]
# Print the top_element
# Your code here

Hint

Use print(top_element) to display the top book.