Python Functions and Modules: Writing Reusable Code Like a Pro

Why Functions Matter (Hint: Less Code Repetition)

In Python, functions let you create a block of code that you can reuse anytime by calling its name. Define it once, then call it wherever you need it—no copy-pasting required.

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Function Basics: The Recipe for Success

Here’s how to define and use a function:

def greet_user(name):
    print(f"Hello, {name}!")

greet_user("Alice")

• def defines the function.
• Parameters (like name) allow input, making functions adaptable.
• Return Values give you results back, so it’s not all output.

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Modules: Libraries for Everything

Python’s modules are like cheat codes for functions—libraries that come preloaded with code you can use. No need to reinvent the wheel! Import them using import:

import math
print(math.sqrt(16))  # Outputs: 4.0

Popular modules like math, random, and datetime save time and effort. If you’re building something big, you can even create custom modules.

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Practical Example: Creating Your Own Module

Say you need to use greet_user across multiple files. Just save it in a .py file (like greetings.py), then import it wherever you need.

# In greetings.py
def greet_user(name):
    print(f"Hello, {name}!")

# In another file
from greetings import greet_user
greet_user("Alice")

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Functions and modules make your code smarter, faster, and reusable.
Cheers to coding smarter, not harder!

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