The thing is though that after it clicked I realized that decorators in python<\/a><\/strong> are one of the most powerful tools that you will ever employ.<\/p>\n Imagine this:<\/p>\n \ud83d\udc49 You have a function.<\/p>\n \ud83d\udc49 You desire logging, authentication or timing.<\/span><\/p>\n \ud83d\udc49 Instead of rewriting the whole function, you just wrap<\/em> it with a decorator.<\/p>\n Let\u2019s start with the basics.<\/p>\n Decorators Python decorators are functions that act on another function (or even a class) and alter its behavior, without making any permanent changes.<\/p>\n Think of it like this:<\/p>\n You have a plain cake \ud83c\udf70 (your function).<\/p>\n<\/li>\n You add icing and sprinkles (the decorator).<\/p>\n<\/li>\n The cake is still the same inside, but it\u2019s now tastier and prettier.<\/p>\n<\/li>\n<\/ul>\n That\u2019s what decorators do in Python\u2014they add functionality in a clean, reusable way.<\/p>\n Example:<\/strong><\/p>\n Output:<\/strong><\/p>\n See what happened? The say_hello function was wrapped with additional functionality – without me having to alter the core of the functionality.<\/span><\/p>\n The first time I did a web application in Flask (a Python web framework) I observed something.<\/span> We did not rewrite code per page to gain routes.<\/span> Instead, we used a decorator:<\/p>\n The decorator login required immediately verified the presence of a user\u2019s presence via the system-administered login process- no longer did I need to repeat the user logged in logic at every other spot.<\/p>\n That\u2019s when I realized:<\/p>\n Decorators in Python are based on two things:<\/span><\/p>\n Here\u2019s the simple flow:<\/p>\n Example with arguments:<\/strong><\/p>\n Output:<\/strong><\/p>\n There are several ways to use decorators in Python<\/strong>, and knowing them helps you decide which one to use in your project.<\/p>\n Function Decorators<\/strong> \u2013 the most common ones you\u2019ll see.<\/p>\n<\/li>\n Class Decorators<\/strong> \u2013 yes, you can wrap entire classes!<\/p>\n<\/li>\n Built-in Decorators<\/strong> \u2013 like Example of built-in decorator:<\/strong><\/p>\n Here, I use the decorators in Python everywhere.<\/span> Here are some practical uses:<\/p>\n Logging<\/strong> – record the time functions are invoked.<\/span><\/p>\n Authentication<\/strong> – web application secure routes (such as my Flask example).<\/span><\/p>\n Performance Tracking<\/strong> – time a function is taken to execute.<\/span><\/p>\n Validation of inputs<\/strong> – verify inputs before the function is executed.<\/span><\/p>\n I\u2019ve been there too. Here are mistakes I made:<\/p>\n Forgetting to return the inner function (your decorator will break).<\/p>\n<\/li>\n Using decorators without understanding Over-decorating functions (yes, you can go overboard).<\/p>\n<\/li>\n<\/ul>\n![\"\"](\"https:\/\/www.kaashivinfotech.com\/blog\/wp-content\/uploads\/2025\/09\/python-decorators.webp\")
<\/p>\n1. What Are Decorators in Python?<\/h2>\n
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def decorator_function(original_function):\r\n def wrapper_function():\r\n print(\"Before the function runs\")\r\n original_function()\r\n print(\"After the function runs\")\r\n return wrapper_function\r\n\r\n@decorator_function\r\ndef say_hello():\r\n print(\"Hello, World!\")\r\n\r\nsay_hello()\r\n<\/pre>\n
Before the function runs \r\nHello, World! \r\nAfter the function runs \r\n<\/pre>\n
![\"\"](\"https:\/\/www.kaashivinfotech.com\/blog\/wp-content\/uploads\/2025\/09\/Decorators-in-Python2.webp\")
<\/p>\n2. Why Use Decorators in Python?<\/strong><\/h2>\n
@app.route('\/dashboard')\r\n@login_required\r\ndef dashboard():\r\n return \"Welcome to your dashboard!\"\r\n<\/pre>\n\n
3. How Decorators in Python Actually Work<\/strong><\/h2>\n
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def repeat(num_times):\r\n def decorator_repeat(func):\r\n def wrapper(*args, **kwargs):\r\n for _ in range(num_times):\r\n func(*args, **kwargs)\r\n return wrapper\r\n return decorator_repeat\r\n\r\n@repeat(num_times=3)\r\ndef greet(name):\r\n print(f\"Hello {name}!\")\r\n\r\ngreet(\"Python\")\r\n<\/pre>\nHello Python! \r\nHello Python! \r\nHello Python! \r\n<\/pre>\n
![\"\"](\"https:\/\/www.kaashivinfotech.com\/blog\/wp-content\/uploads\/2025\/09\/python-decorator5.webp\")
<\/h2>\n4. Types of Decorators in Python\u00a0<\/strong><\/h2>\n
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@staticmethod<\/code>, @classmethod<\/code>, and @property<\/code>.<\/p>\n<\/li>\n<\/ul>\nclass Person:\r\n def __init__(self, name):\r\n self._name = name\r\n\r\n @property\r\n def name(self):\r\n return self._name\r\n\r\np = Person(\"Alice\")\r\nprint(p.name)\r\n<\/pre>\n
@property<\/code> makes the method behave like an attribute.<\/p>\n5. Real-Life Uses of Decorators in Python<\/h2>\n
import time\r\n\r\ndef timer(func):\r\n def wrapper(*args, **kwargs):\r\n start = time.time()\r\n result = func(*args, **kwargs)\r\n end = time.time()\r\n print(f\"{func.__name__} ran in {end - start:.4f} seconds\")\r\n return result\r\n return wrapper\r\n\r\n@timer\r\ndef process_data():\r\n time.sleep(2)\r\n print(\"Data processed\")\r\n\r\nprocess_data()\r\n<\/pre>\n![\"\"](\"https:\/\/www.kaashivinfotech.com\/blog\/wp-content\/uploads\/2025\/09\/Types-of-Decorators-in-Python.webp\")
<\/h2>\n6. Common Mistakes Beginners Make with Decorators in Python<\/strong><\/h2>\n
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*args<\/code> and **kwargs<\/code>.<\/p>\n<\/li>\nConclusion:<\/h2>\n
Related Reads:<\/strong><\/h2>\n