Decorators and Generators in Python

Decorators

A decorator is a function that modifies the behavior of another function or method without changing its actual implementation. It is commonly used for logging, access control, memoization, and more.

Example of a Decorator

def my_decorator(func):
def wrapper():
print("Something is happening before the function is called.")
func()
print("Something is happening after the function is called.")
return wrapper

@my_decorator
def say_hello():
print("Hello!")

say_hello()
 

Output:

Something is happening before the function is called.
Hello!
Something is happening after the function is called.
        

Generators

A generator is a special type of iterator that yields values one at a time using the yield keyword, making it memory efficient for large data sets.

Example of a Generator

 def count_up_to(n):
    count = 1
    while count <= n:
        yield count
        count += 1

# Using the generator
counter = count_up_to(5)
for num in counter:
    print(num)
        

Output:

1
2
3
4
5
        

Note: The function count_up_to generates numbers lazily, without storing them in memory.

Summary

• Decorators modify function behavior (@my_decorator).
• Generators use yield to return values lazily (def gen(): yield value).