beginner
6 min read
Defining Functions in Python
A function turns a block of code into a named tool you can call by name. Write the steps once, give them a name, and reuse them across your program instead…
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Functions and Modules
Organize Python into reusable functions and modules, manage scope, and build programs that are easier to extend.
Tutorials
Articles in Functions and Modules
Follow these lessons in order, or jump directly to the topic you need.
beginner
7 min read
Function Arguments and Return Values
Arguments are how you feed a function; return values are how it hands you the answer. Master both and you stop writing one-off code and start wiring…
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beginner
7 min read
Importing Modules in Python
An import statement is not a magic incantation. It is a name-resolution request: you tell the running Python program, "find this module and make its names…
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beginner
7 min read
Writing Your First Python Module
A Python module is just a .py file you can reuse from other files. The moment you split one growing script into two files and import one from the other,…
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beginner
14 min read
Practice Exercises: Functions
Reading about functions teaches you the rules. Writing them teaches you the mechanism. These python functions exercises are built so you run code, inspect…
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beginner
7 min read
Lambda Functions for Beginners: Anonymous Functions in Python
You've learned to write functions with def, giving each one a name and a job. Then you meet lambdas and wonder: should I be rewriting everything? The short…
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beginner
9 min read
Scope and Lifetime of Variables in Python
You write a function. It works perfectly. The variable inside it prints exactly what you expected. Then you try to use that same variable outside the…
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beginner
8 min read
Using Built-in Python Functions: A Beginner's Guide
Python ships with a toolbox of ready-made functions. You call them, they do the job, and you move on. No imports. No setup. Just a name, some parentheses,…
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beginner
7 min read
Writing Reusable Python Code: DRY Principles for Beginners
Copy-paste feels fast. It is also how small scripts turn into maintenance traps.
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beginner
7 min read
Practice Exercises: Modules and Imports
Reading about imports is easy. Running them until they work from memory is where the skill actually forms. You can follow a tutorial on Python modules and…
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intermediate
10 min read
How to Organize a Small Python Project
Every Python project starts as a single script that does one job. Then it grows. You add a feature, then another, then a helper function that needs its own…
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beginner
11 min read
Recursion in Python: Trace Calls, Find Base Cases, and Compare with Loops
You write a function. It calls itself. You run it, and either the number is wrong or Python throws a RecursionError at you. Nothing about the code looks…
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beginner
7 min read
How to Create and Import a Local Python Package
Your project has three .py files now, and something strange is happening. Yesterday import helpers worked. Today you moved a file, ran the script from a…
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beginner
9 min read
Python Type Hints: Annotate Function Parameters and Return Values
Your function works perfectly until someone hands it a string where you expected a number. Then it fails three lines deep, far from the call that caused…
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intermediate
8 min read
Python Decorators: Understand and Write a Simple Function Wrapper
You copy a snippet from a tutorial. It works. Then you notice a strange line sitting above the function you actually care about:
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