Python Programming – Class XII State Syllabus Guide

XII Class 

Part 1: Exception Handling

Program 1:

Syntax Error vs Exception

# Syntax Error Example (won't run)

# print("Hello

# Exception Example (will run but gives error)

a = 5

b = 0

try:

print(a / b)

except ZeroDivisionError:

print("You cannot divide by zero!")

Program 2:

Try-Except-Else-Finally

try:

num = int(input("Enter a number: "))

print(100 / num)

except ValueError:

print("That's not a number!")

except ZeroDivisionError:

print("Zero is not allowed!")

else:

print("Division successful!")

finally:

print("End of program.")

Program 3:

Raising Exceptions

def check_age(age):

if age < 18:

raise ValueError("You must be 18 or older!")

return True

try:

check_age(15)

except ValueError as e:

print("Exception:", e)

Program 4:

User-Defined Exception

class UnderAgeError(Exception):

pass

def vote(age):

if age < 18:

raise UnderAgeError("You are under age!")

else:

print("You can vote!")

try:

vote(16)

except UnderAgeError as e:

print("Custom Exception:", e)

Program 5:

Built-in Exception Classes

print(dir(__builtins__)) # Shows all built-in exceptions

 Part 2: File Handling

Program 1:

Text File (Write & Read)

# writing to text file

with open("sample.txt", "w") as f:

f.write("Hello from CloudElixir!\n")

f.write("Python is easy.")

# reading from text file

with open("sample.txt", "r") as f:

content = f.read()

print("File content:\n", content)

Note: It creates a file automaticlaly

Program 2:

File Access Modes

# w = write, r = read, a = append, w+ = read/write

with open("sample.txt", "a") as f:

f.write("\nAppending more lines.")

Program 3:

Binary File Using

import pickle

data = {"name": "Venky", "age": 21, "city": "Bangalore"}

# writing binary

with open("data.pkl", "wb") as f:

pickle.dump(data, f)

# reading binary

with open("data.pkl", "rb") as f:

loaded = pickle.load(f)

print("Binary file content:", loaded)

Note: after the execution it will create file.

----------------------------------------------------------------------------------

Filename	Description
sample.txt	Text file with written content
data.pkl	Binary file using pickle module
exceptions_filehandling.py	Full program file combining everything

(For the full code by combining  all the code use the below one)

Full Python File

exceptions_filehandling.py

import pickle

# EXCEPTION HANDLING

print("\n--- Exception Handling ---")

try:

num = int(input("Enter a number: "))

print(100 / num)

except ValueError:

print("That's not a number!")

except ZeroDivisionError:

print("Zero is not allowed!")

else:

print("Division successful!")

finally:

print("End of division block.\n")

# RAISING EXCEPTION

def check_age(age):

if age < 18:

raise ValueError("You must be 18 or older!")

try:

check_age(16)

except ValueError as e:

print("Raised Exception:", e)

# USER DEFINED EXCEPTION

class UnderAgeError(Exception):

pass

def vote(age):

if age < 18:

raise UnderAgeError("You are under age!")

try:

vote(17)

except UnderAgeError as e:

print("Custom Exception:", e)

# FILE HANDLING

print("\n--- File Handling ---")

# Writing text file

with open("sample.txt", "w") as f:

f.write("Python File Handling\nLine 2 here.")

# Reading text file

with open("sample.txt", "r") as f:

print("Text File Content:\n", f.read())

# Writing binary file

data = {"name": "Venkatesh", "age": 21}

with open("data.pkl", "wb") as f:

pickle.dump(data, f)

# Reading binary file

with open("data.pkl", "rb") as f:

print("Binary File Content:\n", pickle.load(f))

-----------*----------------------------*------------------------------*------------------------------

  Python Programming Chapter2

🔹 What is a Stack?

A Stack is a linear data structure that follows the LIFO (Last In First Out) principle.
Think of it like a stack of plates – you can only add (push) or remove (pop) the top one.

🔹 Basic Stack Operations in Python

• PUSH (Add element to the top)
• POP (Remove element from the top)

Program 1:

Stack Implementation using List

stack = []

# PUSH operation

stack.append(10)

stack.append(20)

stack.append(30)

print("Stack after push:", stack)

# POP operation

print("Popped element:", stack.pop())

print("Stack after pop:", stack)

Expressions – Prefix, Infix, Postfix

Notation	Example	Order
Infix	A + B	Operand + Operator + Operand
Prefix	+ A B	Operator before operands
Postfix	A B +	Operator after operands

Program 2:

Infix to Postfix Conversion

def infix_to_postfix(expression):

precedence = {'+':1, '-':1, '*':2, '/':2, '^':3}

stack = []

result = ""

for char in expression:

if char.isalnum():

result += char

elif char == '(':

stack.append(char)

elif char == ')':

while stack and stack[-1] != '(':

result += stack.pop()

stack.pop() # remove '('

else:

while stack and stack[-1] != '(' and precedence[char] <= precedence.get(stack[-1], 0):

result += stack.pop()

stack.append(char)

while stack:

result += stack.pop()

return result

# Test

exp = input("Enter Infix Expression: ")

print("Postfix Expression:", infix_to_postfix(exp))

Program 3:

Evaluate Postfix Expression

def evaluate_postfix(expression):
    stack = []
    for char in expression:
        if char.isdigit():
            stack.append(int(char))
        else:
            b = stack.pop()
            a = stack.pop()
            if char == '+':
                stack.append(a + b)
            elif char == '-':
                stack.append(a - b)
            elif char == '*':
                stack.append(a * b)
            elif char == '/':
                stack.append(a / b)
    return stack.pop()
# Test
exp = input("Enter Postfix Expression (Single-digit operands): ")
print("Result:", evaluate_postfix(exp))

Final Python File (Full Code For Stack_Operation)

stack_operations.py

# Stack Operations, Infix to Postfix, and Evaluation

# PUSH and POP

stack = []

def push():

element = input("Enter element to push: ")

stack.append(element)

print("Stack:", stack)

def pop():

if not stack:

print("Stack is empty!")

else:

print("Popped element:", stack.pop())

print("Stack:", stack)

# Infix to Postfix

def infix_to_postfix(expression):

precedence = {'+':1, '-':1, '*':2, '/':2, '^':3}

stack = []

result = ""

for char in expression:

if char.isalnum():

result += char

elif char == '(':

stack.append(char)

elif char == ')':

while stack and stack[-1] != '(':

result += stack.pop()

stack.pop()

else:

while stack and stack[-1] != '(' and precedence[char] <= precedence.get(stack[-1], 0):

result += stack.pop()

stack.append(char)

while stack:

result += stack.pop()

return result

# Evaluate Postfix

def evaluate_postfix(expression):

stack = []

for char in expression:

if char.isdigit():

stack.append(int(char))

else:

b = stack.pop()

a = stack.pop()

if char == '+':

stack.append(a + b)

elif char == '-':

stack.append(a - b)

elif char == '*':

stack.append(a * b)

elif char == '/':

stack.append(a / b)

return stack.pop()

# Menu

while True:

print("\n1. PUSH\n2. POP\n3. Infix to Postfix\n4. Evaluate Postfix\n5. Exit")

ch = int(input("Enter your choice: "))

if ch == 1:

push()

elif ch == 2:

pop()

elif ch == 3:

infix = input("Enter Infix Expression: ")

print("Postfix:", infix_to_postfix(infix))

elif ch == 4:

postfix = input("Enter Postfix Expression (digits only): ")

print("Result:", evaluate_postfix(postfix))

elif ch == 5:

break

else:

print("Invalid choice!")

 Python Programming Chapter3

Queue (FIFO – First In First Out)

Program 1:

Queue Implementation using List

queue = []

def insert():

element = input("Enter element to insert: ")

queue.append(element)

print("Queue:", queue)

def delete():

if not queue:

print("Queue is empty!")

else:

removed = queue.pop(0)

print("Deleted element:", removed)

print("Queue:", queue)

while True:

print("\n1. INSERT\n2. DELETE\n3. EXIT")

choice = int(input("Enter your choice: "))

if choice == 1:

insert()

elif choice == 2:

delete()

elif choice == 3:

break

else:

print("Invalid choice!")

 Introduction to DeQueue (Double-Ended Queue)

A DeQueue (Double-Ended Queue) allows insertion and deletion from both ends:

• Front & Rear insert
• Front & Rear delete

Python provides this through the collections.deque module.

Program 2:

DeQueue Implementation using collections.deque




from collections import deque

dq = deque()

def add_front():

element = input("Enter element to add at front: ")

dq.appendleft(element)

print("DeQueue:", dq)

def add_rear():

element = input("Enter element to add at rear: ")

dq.append(element)

print("DeQueue:", dq)

def delete_front():

if not dq:

print("DeQueue is empty!")

else:

print("Deleted from front:", dq.popleft())

print("DeQueue:", dq)

def delete_rear():

if not dq:

print("DeQueue is empty!")

else:

print("Deleted from rear:", dq.pop())

print("DeQueue:", dq)

while True:

print("\n1. Add Front\n2. Add Rear\n3. Delete Front\n4. Delete Rear\n5. Exit")

ch = int(input("Enter your choice: "))

if ch == 1:

add_front()

elif ch == 2:

add_rear()

elif ch == 3:

delete_front()

elif ch == 4:

delete_rear()

elif ch == 5:

break

else:

print("Invalid choice!")

Final Python File (Full Code For Queue_Operation)

from collections import deque

# Simple Queue

queue = []

def insert():

element = input("Enter element to insert in Queue: ")

queue.append(element)

print("Queue:", queue)

def delete():

if not queue:

print("Queue is empty!")

else:

print("Deleted:", queue.pop(0))

print("Queue:", queue)

# DeQueue

dq = deque()

def add_front():

element = input("Enter element to add at front of DeQueue: ")

dq.appendleft(element)

print("DeQueue:", dq)

def add_rear():

element = input("Enter element to add at rear of DeQueue: ")

dq.append(element)

print("DeQueue:", dq)

def delete_front():

if not dq:

print("DeQueue is empty!")

else:

print("Deleted from front:", dq.popleft())

print("DeQueue:", dq)

def delete_rear():

if not dq:

print("DeQueue is empty!")

else:

print("Deleted from rear:", dq.pop())

print("DeQueue:", dq)

# Menu

while True:

print("\nQueue Operations:\n1. INSERT (Queue)\n2. DELETE (Queue)")

print("DeQueue Operations:\n3. Add Front\n4. Add Rear\n5. Delete Front\n6. Delete Rear\n7. Exit")

ch = int(input("Enter choice: "))

if ch == 1:

insert()

elif ch == 2:

delete()

elif ch == 3:

add_front()

elif ch == 4:

add_rear()

elif ch == 5:

delete_front()

elif ch == 6:

delete_rear()

elif ch == 7:

break

else:

print("Invalid choice!")