The Python “Mutable Default Argument” Trap (Why Your List is Not Empty)
This is the most famous “gotcha” in all of Python: the Mutable Default Argument bug. It’s a bug that confuses every developer exactly once. Look…
How to Fix: TypeError: ‘int’ object is not callable
This error is very similar to 'str' object is not callable. One common error in Python is the TypeError int not callable, which means: “You…
How to Fix: TypeError: ‘NoneType’ object is not iterable
This error is simple: you tried to use a for loop on a variable, but that variable was None. In Python, this will raise a…
How to Fix: TypeError: ‘NoneType’ object is not callable
The NoneType object is not callable error means you are trying to “call” a variable (by putting () after it) as if it were a…
Unpacking with * and **: How to Call Functions with Lists and Dictionaries
You’ve learned how to define a function that accepts *args and **kwargs. Now, we’ll learn the opposite: how to call a function using * and…
How to Fix: RecursionError: maximum recursion depth exceeded
This error means a function is calling itself over and over again, in an infinite loop, until it hits a safety limit set by Python…
Python *args and **kwargs: How to Write Flexible Functions
Sometimes you don’t know how many arguments a user might pass to your function, which is why understanding Python args and kwargs is essential. Think…
Python Lambda Functions: Anonymous Functions Explained
Sometimes you need a tiny function for just one quick task. Python Lambda Functions are perfect for these occasions. Writing a full def my_function(): block…
Python Beginner Project: Build a Simple Calculator
Following up on our Number Guessing Game, today we’re building a tool that actually does something useful: a calculator. This project is perfect for practicing…
How to Write Your First Python Function (A Beginner’s Guide)
So far, you’ve learned to write code that runs from top to bottom. But what if you need to perform a specific task multiple times…
