Python Practice Questions

Topic-based coding problems with sample test cases — build confidence step by step.

Exception Handling Practice

Handle runtime errors with try, except, else, finally and custom exceptions.

1
Catch Division by Zero
Easy
Write a program that divides two integers and catches ZeroDivisionError, printing 'Cannot divide by zero'.
Input Format
First line: a. Second line: b.
Output Format
Print the quotient, or the error message.
Sample Test Cases
Sample Input 1
10
0
Sample Output 1
Cannot divide by zero
Sample Input 2
4
0
Sample Output 2
Cannot divide by zero
Sample Input 3
8
2
Sample Output 3
4.0
2
Catch ValueError on int()
Easy
Write a program that converts input to int and catches ValueError, printing 'Invalid number'.
Input Format
A single line containing the input.
Output Format
Print the integer, or 'Invalid number'.
Sample Test Cases
Sample Input 1
abc
Sample Output 1
Invalid number
Sample Input 2
42
Sample Output 2
42
Sample Input 3
1.5
Sample Output 3
Invalid number
3
Try-Except with Multiple Values
Easy
Write a program that reads two numbers and prints their sum, catching any input error.
Input Format
A single line containing two values.
Output Format
Print the sum, or 'Invalid input'.
Sample Test Cases
Sample Input 1
2 3
Sample Output 1
5
Sample Input 2
10 x
Sample Output 2
Invalid input
Sample Input 3
1 2 3
Sample Output 3
6
4
Simple try-except
Easy
Write a program that accesses an out-of-range list index and catches IndexError.
Input Format
No input (list [1,2,3], index 5).
Output Format
Print 'Index out of range'.
Sample Test Cases
Sample Input 1

                      		
                      
                        
Sample Output 1

                        
Index out of range

                      		
                    

                                      

                      
                        
Sample Input 2

                        

                      		
                      
                        
Sample Output 2

                        
Index out of range

                      		
                    

                                      

                      
                        
Sample Input 3

                        

                      		
                      
                        
Sample Output 3

                        
Index out of range

                      		
                    

                                  

              
              
                          

                      

              

                
5

                
Catch KeyError

                Easy
              


              
Write a program that looks up a missing key in a dict and catches KeyError.


              

                

                  
Input Format

                  
A single line containing a key to look up (dict = {'a':1,'b':2}).

                

                

                  
Output Format

                  
Print the value, or 'Key not found'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
z

                      		
                      
                        
Sample Output 1

                        
Key not found

                      		
                    

                                      

                      
                        
Sample Input 2

                        
a

                      		
                      
                        
Sample Output 2

                        
1

                      		
                    

                                      

                      
                        
Sample Input 3

                        
b

                      		
                      
                        
Sample Output 3

                        
2

                      		
                    

                                  

              
              
                          

                      

              

                
6

                
Catch TypeError

                Easy
              


              
Write a program that tries to add a string and an integer and catches TypeError.


              

                

                  
Input Format

                  
No input.

                

                

                  
Output Format

                  
Print 'Type error occurred'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        

                      		
                      
                        
Sample Output 1

                        
Type error occurred

                      		
                    

                                      

                      
                        
Sample Input 2

                        

                      		
                      
                        
Sample Output 2

                        
Type error occurred

                      		
                    

                                      

                      
                        
Sample Input 3

                        

                      		
                      
                        
Sample Output 3

                        
Type error occurred

                      		
                    

                                  

              
              
                          

                      

              

                
7

                
Try-Except-Finally

                Easy
              


              
Write a program that tries to convert to int and always prints 'Done' in finally.


              

                

                  
Input Format

                  
A single line containing the input.

                

                

                  
Output Format

                  
Print the int or error, then 'Done'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
5

                      		
                      
                        
Sample Output 1

                        
5
Done

                      		
                    

                                      

                      
                        
Sample Input 2

                        
abc

                      		
                      
                        
Sample Output 2

                        
Invalid number
Done

                      		
                    

                                      

                      
                        
Sample Input 3

                        
7

                      		
                      
                        
Sample Output 3

                        
7
Done

                      		
                    

                                  

              
              
                          

                      

              

                
8

                
Catch Multiple Exceptions

                Easy
              


              
Write a program that catches both ValueError and ZeroDivisionError.


              

                

                  
Input Format

                  
First line: a. Second line: b.

                

                

                  
Output Format

                  
Print the result, or the specific error message.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
5
0

                      		
                      
                        
Sample Output 1

                        
Cannot divide by zero

                      		
                    

                                      

                      
                        
Sample Input 2

                        
7
0

                      		
                      
                        
Sample Output 2

                        
Cannot divide by zero

                      		
                    

                                      

                      
                        
Sample Input 3

                        
6
3

                      		
                      
                        
Sample Output 3

                        
2.0

                      		
                    

                                  

              
              
                          

                      

              

                
9

                
Exception with else Block

                Easy
              


              
Write a program with try-except-else that prints 'No error' when the conversion succeeds.


              

                

                  
Input Format

                  
A single line containing an integer string.

                

                

                  
Output Format

                  
Print the integer, then 'No error'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
42

                      		
                      
                        
Sample Output 1

                        
42
No error

                      		
                    

                                      

                      
                        
Sample Input 2

                        
abc

                      		
                      
                        
Sample Output 2

                        
Invalid number

                      		
                    

                                      

                      
                        
Sample Input 3

                        
7

                      		
                      
                        
Sample Output 3

                        
7
No error

                      		
                    

                                  

              
              
                          

                      

              

                
10

                
Handle File Not Found

                Easy
              


              
Write a program that tries to open 'missing.txt' and catches FileNotFoundError.


              

                

                  
Input Format

                  
No input.

                

                

                  
Output Format

                  
Print 'File not found'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        

                      		
                      
                        
Sample Output 1

                        
File not found

                      		
                    

                                      

                      
                        
Sample Input 2

                        

                      		
                      
                        
Sample Output 2

                        
File not found

                      		
                    

                                      

                      
                        
Sample Input 3

                        

                      		
                      
                        
Sample Output 3

                        
File not found

                      		
                    

                                  

              
              
                          

                        


      
      

                              

              

                
1

                
Raising an Exception

                Medium
              


              
Write a program that raises ValueError with message 'Negative not allowed' if input is negative.


              

                

                  
Input Format

                  
A single line containing an integer.

                

                

                  
Output Format

                  
Print the number, or the error message.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
-5

                      		
                      
                        
Sample Output 1

                        
Negative not allowed

                      		
                    

                                      

                      
                        
Sample Input 2

                        
10

                      		
                      
                        
Sample Output 2

                        
10

                      		
                    

                                      

                      
                        
Sample Input 3

                        
-1

                      		
                      
                        
Sample Output 3

                        
Negative not allowed

                      		
                    

                                  

              
              
                          

                      

              

                
2

                
Custom Exception Class

                Medium
              


              
Write a custom exception class NegativeError that inherits Exception, and raise it for negative input.


              

                

                  
Input Format

                  
A single line containing an integer.

                

                

                  
Output Format

                  
Print 'Custom error: Negative value', or the number.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
-3

                      		
                      
                        
Sample Output 1

                        
Custom error: Negative value

                      		
                    

                                      

                      
                        
Sample Input 2

                        
5

                      		
                      
                        
Sample Output 2

                        
5

                      		
                    

                                      

                      
                        
Sample Input 3

                        
-1

                      		
                      
                        
Sample Output 3

                        
Custom error: Negative value

                      		
                    

                                  

              
              
                          

                      

              

                
3

                
Try-Except-Else-Finally

                Medium
              


              
Write a program that divides two numbers and prints 'Success' in else and 'Cleanup done' in finally.


              

                

                  
Input Format

                  
First line: a. Second line: b.

                

                

                  
Output Format

                  
Print the quotient, 'Success', and 'Cleanup done'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
8
2

                      		
                      
                        
Sample Output 1

                        
4.0
Success
Cleanup done

                      		
                    

                                      

                      
                        
Sample Input 2

                        
10
0

                      		
                      
                        
Sample Output 2

                        
Cannot divide by zero
Cleanup done

                      		
                    

                                      

                      
                        
Sample Input 3

                        
9
3

                      		
                      
                        
Sample Output 3

                        
3.0
Success
Cleanup done

                      		
                    

                                  

              
              
                          

                      

              

                
4

                
Nested Try-Except

                Medium
              


              
Write a program with an inner try that converts a value and an outer try that performs division.


              

                

                  
Input Format

                  
First line: a. Second line: b.

                

                

                  
Output Format

                  
Print the result or appropriate error message.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
10
0

                      		
                      
                        
Sample Output 1

                        
Cannot divide by zero

                      		
                    

                                      

                      
                        
Sample Input 2

                        
abc
2

                      		
                      
                        
Sample Output 2

                        
Cannot divide by zero

                      		
                    

                                      

                      
                        
Sample Input 3

                        
10
5

                      		
                      
                        
Sample Output 3

                        
2.0

                      		
                    

                                  

              
              
                          

                      

              

                
5

                
Catch and Reraise

                Medium
              


              
Write a program that catches ZeroDivisionError, prints 'Caught', then re-raises it.


              

                

                  
Input Format

                  
First line: a. Second line: b (0).

                

                

                  
Output Format

                  
Print 'Caught' and the re-raised error message.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
5
0

                      		
                      
                        
Sample Output 1

                        
Caught
Cannot divide by zero

                      		
                    

                                      

                      
                        
Sample Input 2

                        
5
0

                      		
                      
                        
Sample Output 2

                        
Caught
Cannot divide by zero

                      		
                    

                                      

                      
                        
Sample Input 3

                        
10
2

                      		
                      
                        
Sample Output 3

                        
Caught
5.0

                      		
                    

                                  

              
              
                          

                      

              

                
6

                
Exception Hierarchy

                Medium
              


              
Write a program that catches ArithmeticError (parent of ZeroDivisionError) for division by zero.


              

                

                  
Input Format

                  
First line: a. Second line: b.

                

                

                  
Output Format

                  
Print 'Arithmetic error caught'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
4
0

                      		
                      
                        
Sample Output 1

                        
Arithmetic error caught

                      		
                    

                                      

                      
                        
Sample Input 2

                        
9
0

                      		
                      
                        
Sample Output 2

                        
Arithmetic error caught

                      		
                    

                                      

                      
                        
Sample Input 3

                        
8
4

                      		
                      
                        
Sample Output 3

                        
Arithmetic error caught
2.0

                      		
                    

                                  

              
              
                          

                      

              

                
7

                
Index Error with Details

                Medium
              


              
Write a program that accesses list index out of range and prints the valid index range instead.


              

                

                  
Input Format

                  
No input (list [10,20,30], index 5).

                

                

                  
Output Format

                  
Print 'Valid indices: 0 to 2'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        

                      		
                      
                        
Sample Output 1

                        
Valid indices: 0 to 2

                      		
                    

                                      

                      
                        
Sample Input 2

                        

                      		
                      
                        
Sample Output 2

                        
Valid indices: 0 to 2

                      		
                    

                                      

                      
                        
Sample Input 3

                        

                      		
                      
                        
Sample Output 3

                        
Valid indices: 0 to 2

                      		
                    

                                  

              
              
                          

                      

              

                
8

                
Attribute Error Handling

                Medium
              


              
Write a program that accesses a non-existent attribute on an object and catches AttributeError.


              

                

                  
Input Format

                  
No input (empty class with no attributes, access .missing).

                

                

                  
Output Format

                  
Print 'Attribute not found'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        

                      		
                      
                        
Sample Output 1

                        
Attribute not found

                      		
                    

                                      

                      
                        
Sample Input 2

                        

                      		
                      
                        
Sample Output 2

                        
Attribute not found

                      		
                    

                                      

                      
                        
Sample Input 3

                        

                      		
                      
                        
Sample Output 3

                        
Attribute not found

                      		
                    

                                  

              
              
                          

                      

              

                
9

                
Chained Exceptions

                Medium
              


              
Write a program that catches ValueError and re-raises it as RuntimeError with 'from e'.


              

                

                  
Input Format

                  
A single line containing the input.

                

                

                  
Output Format

                  
Print 'Converted to RuntimeError'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
abc

                      		
                      
                        
Sample Output 1

                        
Converted to RuntimeError

                      		
                    

                                      

                      
                        
Sample Input 2

                        
5

                      		
                      
                        
Sample Output 2

                        
Converted to RuntimeError

                      		
                    

                                      

                      
                        
Sample Input 3

                        
x

                      		
                      
                        
Sample Output 3

                        
Converted to RuntimeError

                      		
                    

                                  

              
              
                          

                      

              

                
10

                
Try-Except with Loop

                Medium
              


              
Write a program that keeps asking for a valid integer until one is entered (simulate: use 2 attempts from input).


              

                

                  
Input Format

                  
Two lines: first invalid value, then valid value.

                

                

                  
Output Format

                  
Print the valid integer.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
abc
42

                      		
                      
                        
Sample Output 1

                        
42

                      		
                    

                                      

                      
                        
Sample Input 2

                        
x
10

                      		
                      
                        
Sample Output 2

                        
10

                      		
                    

                                      

                      
                        
Sample Input 3

                        
a
b
5

                      		
                      
                        
Sample Output 3

                        
5

                      		
                    

                                  

              
              
                          

                        


      
      

                              

              

                
1

                
Bank Withdrawal with Custom Errors

                Hard
              


              
Write a class BankAccount with withdraw(amount) that raises custom errors for negative amount and insufficient balance.


              

                

                  
Input Format

                  
First line: balance. Second line: withdrawal.

                

                

                  
Output Format

                  
Print 'Withdrawn' or the specific error message.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
100
150

                      		
                      
                        
Sample Output 1

                        
Insufficient balance

                      		
                    

                                      

                      
                        
Sample Input 2

                        
500
100

                      		
                      
                        
Sample Output 2

                        
Withdrawn

                      		
                    

                                      

                      
                        
Sample Input 3

                        
100
150

                      		
                      
                        
Sample Output 3

                        
Insufficient balance

                      		
                    

                                  

              
              
                          

                      

              

                
2

                
File Processing with Errors

                Hard
              


              
Write a program that reads a filename from input and prints 'File opened' if it exists, catching FileNotFoundError and PermissionError.


              

                

                  
Input Format

                  
A single line containing a filename.

                

                

                  
Output Format

                  
Print the appropriate message.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
missing.txt

                      		
                      
                        
Sample Output 1

                        
File not found

                      		
                    

                                      

                      
                        
Sample Input 2

                        
data.txt

                      		
                      
                        
Sample Output 2

                        
File not found

                      		
                    

                                      

                      
                        
Sample Input 3

                        
missing.csv

                      		
                      
                        
Sample Output 3

                        
File not found

                      		
                    

                                  

              
              
                          

                      

              

                
3

                
Custom Exception with Attributes

                Hard
              


              
Write a custom exception InvalidAgeError that carries the age value, and raise it for age outside 0-150.


              

                

                  
Input Format

                  
A single line containing the age.

                

                

                  
Output Format

                  
Print 'Invalid age: [age]' or the age.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
200

                      		
                      
                        
Sample Output 1

                        
Invalid age: 200

                      		
                    

                                      

                      
                        
Sample Input 2

                        
25

                      		
                      
                        
Sample Output 2

                        
25

                      		
                    

                                      

                      
                        
Sample Input 3

                        
-5

                      		
                      
                        
Sample Output 3

                        
Invalid age: -5

                      		
                    

                                  

              
              
                          

                      

              

                
4

                
Retry Logic with Exceptions

                Hard
              


              
Write a program that attempts an operation up to 3 times, catching exceptions and printing the attempt number.


              

                

                  
Input Format

                  
A single line containing a value that fails twice then succeeds.

                

                

                  
Output Format

                  
Print attempt numbers and final success.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
0

                      		
                      
                        
Sample Output 1

                        
Attempt 1 failed
Attempt 2 failed
Success

                      		
                    

                                      

                      
                        
Sample Input 2

                        
0
0
1

                      		
                      
                        
Sample Output 2

                        
Attempt 1 failed
Attempt 2 failed
Success

                      		
                    

                                      

                      
                        
Sample Input 3

                        
5

                      		
                      
                        
Sample Output 3

                        
Success

                      		
                    

                                  

              
              
                          

                      

              

                
5

                
Assertion for Validation

                Hard
              


              
Write a program that uses assert to check that a number is positive, catching AssertionError.


              

                

                  
Input Format

                  
A single line containing an integer.

                

                

                  
Output Format

                  
Print the number, or 'Assertion failed'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
-1

                      		
                      
                        
Sample Output 1

                        
Assertion failed

                      		
                    

                                      

                      
                        
Sample Input 2

                        
5

                      		
                      
                        
Sample Output 2

                        
5

                      		
                    

                                      

                      
                        
Sample Input 3

                        
0

                      		
                      
                        
Sample Output 3

                        
Assertion failed

                      		
                    

                                  

              
              
                          

                      

              

                
6

                
Exception in OOP Methods

                Hard
              


              
Write a class Calculator with divide(a, b) that raises ZeroDivisionError with a custom message.


              

                

                  
Input Format

                  
First line: a. Second line: b.

                

                

                  
Output Format

                  
Print the result, or the error message.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
6
0

                      		
                      
                        
Sample Output 1

                        
Cannot divide by zero

                      		
                    

                                      

                      
                        
Sample Input 2

                        
9
3

                      		
                      
                        
Sample Output 2

                        
3.0

                      		
                    

                                      

                      
                        
Sample Input 3

                        
9
0

                      		
                      
                        
Sample Output 3

                        
Cannot divide by zero

                      		
                    

                                  

              
              
                          

                      

              

                
7

                
Multi-Layer Error Propagation

                Hard
              


              
Write functions inner() that raises ValueError, and outer() that catches it and prints 'Handled in outer'.


              

                

                  
Input Format

                  
No input.

                

                

                  
Output Format

                  
Print 'Handled in outer'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        

                      		
                      
                        
Sample Output 1

                        
Handled in outer

                      		
                    

                                      

                      
                        
Sample Input 2

                        

                      		
                      
                        
Sample Output 2

                        
Handled in outer

                      		
                    

                                      

                      
                        
Sample Input 3

                        

                      		
                      
                        
Sample Output 3

                        
Handled in outer

                      		
                    

                                  

              
              
                          

                      

              

                
8

                
Cleanup with finally (Resource)

                Hard
              


              
Write a program that simulates opening a resource, raises an exception, and closes the resource in finally.


              

                

                  
Input Format

                  
A single line containing 1 to trigger the error, else 0.

                

                

                  
Output Format

                  
Print 'Resource acquired', error message if triggered, and 'Resource released'.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
1

                      		
                      
                        
Sample Output 1

                        
Resource acquired
Error occurred
Resource released

                      		
                    

                                      

                      
                        
Sample Input 2

                        
0

                      		
                      
                        
Sample Output 2

                        
Resource acquired
Resource released

                      		
                    

                                      

                      
                        
Sample Input 3

                        
1

                      		
                      
                        
Sample Output 3

                        
Resource acquired
Error occurred
Resource released

                      		
                    

                                  

              
              
                          

                      

              

                
9

                
User-Defined Error Hierarchy

                Hard
              


              
Write base exception AppError and derived NetworkError and DataError. Raise NetworkError and catch AppError.


              

                

                  
Input Format

                  
A single line containing 'network' or 'data'.

                

                

                  
Output Format

                  
Print the caught error message.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
network

                      		
                      
                        
Sample Output 1

                        
Network error occurred

                      		
                    

                                      

                      
                        
Sample Input 2

                        
data

                      		
                      
                        
Sample Output 2

                        
Data error occurred

                      		
                    

                                      

                      
                        
Sample Input 3

                        
network

                      		
                      
                        
Sample Output 3

                        
Network error occurred

                      		
                    

                                  

              
              
                          

                      

              

                
10

                
Convert Exception to Message

                Hard
              


              
Write a program that reads two numbers, attempts division, and converts any exception to a friendly message using str(e).


              

                

                  
Input Format

                  
First line: a. Second line: b.

                

                

                  
Output Format

                  
Print the friendly error message or the quotient.

                

              


                              
Sample Test Cases

                

                                      

                      
                        
Sample Input 1

                        
10
0

                      		
                      
                        
Sample Output 1

                        
division by zero

                      		
                    

                                      

                      
                        
Sample Input 2

                        
5
2

                      		
                      
                        
Sample Output 2

                        
2.5

                      		
                    

                                      

                      
                        
Sample Input 3

                        
5
0

                      		
                      
                        
Sample Output 3

                        
division by zero