🧠 return vs print() in Python

These are not interchangeable.

def add(a, b):
    print(a + b)

Calling:

result = add(2, 3)

prints:

5

But:

result

is actually:

None

Now compare:

def add(a, b):
    return a + b

This time:

result = add(2, 3)

gives:

result == 5

print() sends something to the screen.
return sends a value back to the caller.

That distinction becomes extremely important once functions start calling other functions.

🐍 Python Performance Optimization

Python Performance Optimization: Make Your Code Faster
Writing Python code that works is only the beginning. For real-world applications, performance matters.

Here are some techniques that can significantly improve Python performance:

⚡️ 1. Use the right data structures
Choosing a set instead of a list for frequent membership checks can dramatically reduce lookup time.
⚡️ 2. Avoid unnecessary loops
Use built-in functions, comprehensions, and optimized libraries such as NumPy when appropriate.
⚡️ 3. Profile before optimizing
Tools like cProfile and timeit help identify the actual bottlenecks instead of optimizing blindly.
⚡️ 4. Reduce unnecessary memory usage
Generators can process large datasets without loading everything into memory at once.
⚡️ 5. Use vectorization for data processing
NumPy operations can be much faster than manually looping through millions of values.

💡 Key principle:
Don't optimize what you haven't measured.