Practice Top 30 Python Programming Questions on Decorators and Generators

Practice Top 30 Python Programming Questions on Decorators and Generators

Q1.  Write a generator function count_up_to(n) that yields numbers from 1 to n.  

Input:  
Enter n: 5  
 
Expected Output:  
1  
2  
3  
4  
5  

Q2. Write a generator function even_numbers(n) that yields even numbers up to n.  

Input:  
Enter n: 6  

Expected Output:  
2  
4  
6  

Q3. Create a generator expression to generate squares of numbers from 1 to 5.  

Expected Output:  
1  
4  
9  
16  
25

Q4. Write a generator infinite_sequence() that yields numbers starting from 1 indefinitely. Print the first 5 numbers from the generator.  

Expected Output:  
1  
2  
3  
4  
5

Q5. Write a decorator log_function_call that logs a message before and after calling a function. Use it on a function greet() that prints "Hello!".  

Expected Output:  
Calling function greet...  
Hello!  
Finished calling function greet. 

Q6. Write a generator function reverse_string(s) that yields characters of a string in reverse order.  

Input:  
Enter a string: Python  

Expected Output:  
n  
o  
h  
t  
y  
P 

Q7. Write a decorator uppercase that converts the result of a function returning a string to uppercase. Apply it to a function say_hello() that returns "hello".  

Expected Output:  
HELLO

Q8. Write two generator functions, generate_numbers(n) to yield numbers up to n, and square_numbers(gen) to yield squares of numbers from another generator.  

Input:  
Enter n: 3  

Expected Output:  
1  
4  
9 

Q9. Write a decorator timer to calculate the time taken by a function to execute. Apply it to a function slow_function() that sleeps for 1 second.  

Expected Output:  
Execution time: 1.00 seconds.

Q10. Write a generator fibonacci(n) that yields the first n numbers in the Fibonacci sequence.  

Input:  
Enter n: 5  

Expected Output:  
0  
1  
1  
2  
3 

Q11. Write a decorator validate_positive that checks if the input to a function is a positive number. If not, raise a ValueError. Apply it to a function double(n) that doubles the input number.  

Input:  
Enter a number: -5  

Expected Output:  
ValueError: Input must be a positive number.

Q12. Write a generator function filter_odd(numbers) that takes a list of numbers and yields only the odd ones.  

Input:  
Enter numbers: [1, 2, 3, 4, 5]  

Expected Output:  
1  
3  
5

Q13. Write a decorator count_calls that counts the number of times a function is called. Apply it to a function greet() that prints "Hello!".  

Input:  
Call greet() three times.  

Expected Output:  
Hello!  
Hello!  
Hello!  
Function greet was called 3 times.

Q14.  Write two generator functions:  
- generate_letters(s) to yield each letter of a string.  
- capitalize_letters(gen) to yield the capitalized version of letters from another generator.  

Input:  
Enter a string: abc  

Expected Output:  
A  
B  
C

Q15. Write a decorator memoize that caches the results of a function. Apply it to a function factorial(n) that calculates the factorial of a number.  

Input:  
Enter a number: 5  

Expected Output:  
Factorial of 5 is 120.

Q16. Write a generator function nested_numbers() that yields lists of numbers, and another generator flatten(gen) to flatten these lists into a single sequence of numbers.  

Input:  
nested_numbers() yields: [[1, 2], [3, 4], [5]]  

Expected Output:  
1  
2  
3  
4  
5

Q17. Write a decorator add_greeting that adds "Hi, " before the output of a function that returns a name. Apply it to a function get_name() that returns a name.  

Input:  
Name: Alice  

Expected Output:  
Hi, Alice

Q18. Write a generator function generate_primes(n) that yields prime numbers less than or equal to n.  

Input:  
Enter n: 10  

Expected Output:  
2  
3  
5  
7 

Q19. Write a decorator repeat(times) that repeats the execution of a function a specified number of times. Apply it to a function say_hello() that prints "Hello!".  

Input:  
Repeat 3 times.  

Expected Output:  
Hello!  
Hello!  
Hello! 

Q20. Write a generator multiplication_table(n) that yields the multiplication table of n.  
Input:  
Enter n: 3  

Expected Output:  
3 x 1 = 3  
3 x 2 = 6  
3 x 3 = 9  
3 x 4 = 12  
3 x 5 = 15

Q21. Write a decorator log_arguments that logs the arguments of a function call. Apply it to a function add(a, b) that returns the sum of two numbers.  

Input:  
Add 3 and 5.  

Expected Output:  
Calling add with arguments: (3, 5)  
8 

Q22. Write a generator function repeat_characters(s) that takes a string and yields each character repeated twice.  

Input:  
Enter a string: Hello  

Expected Output:  
HH  
ee  
ll  
ll  
oo 

Q23. Write a decorator generator_timer to calculate the time taken by a generator function to yield all its values. Apply it to a generator count_to(n) that counts up to n.  

Input:  
Count to 3.  
 
Expected Output:  
1  
2  
3 

Q24. Write a generator char_indices(s) that yields each character in a string along with its index.  

Input:  
Enter a string: abc  

Expected Output:  
(0, 'a')  
(1, 'b')  
(2, 'c')

Q25. Write a decorator type_check to validate that the arguments of a function are integers. Apply it to a function add_numbers(a, b) that adds two numbers.  

Input:  
Enter a: 5  
Enter b: abc  

Expected Output:  
TypeError: Arguments must be integers. 

Q26. Write a generator sum_numbers(n) that yields numbers from 1 to n, and then returns their sum.  

Input:  
Enter n: 4  
 
Expected Output:  
1  
2  
3  
4  
Sum is 10.

Q27. Write a decorator check_access that allows function execution only if the username matches a given value. Apply it to a function access_resource() that simulates accessing a resource.  

Input:  
Enter username: admin  
 
Expected Output:  
Access granted to admin.  

Q28. Write a generator powers_of_two(n) that yields powers of two up to n.  

Input:  
Enter n: 16  

Expected Output:  
1  
2  
4  
8  
16 

Q29. Write a decorator execute_if_positive that only allows the decorated function to execute if the argument is positive. Apply it to a function square_number(n) that returns the square of a number.  

Input:  
Enter a number: -3  

Expected Output:  
Condition not met. Function not executed.

Q30. Create a generator expression to generate even numbers from 1 to 10.  

Expected Output:  
2  
4  
6  
8  
10