beginner20 min
Functions
Defining and calling functions, parameters, and return values
What are Functions?
A function is a reusable block of code that performs a specific task. You define a function once and call it many times.
Your First Function
Output
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Functions with Parameters
Parameters let you pass data into a function:
Functions with Parameters
Output
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Return Values
Functions can return values using the return keyword:
Return Values
Output
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Multiple Parameters & Default Values
Default Parameters
Output
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Variable Scope
Variables defined inside a function are local — they don't exist outside:
Variable Scope
Output
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Check Your Understanding
What keyword is used to define a function in Python?
Check Your Understanding
What does this function return: `def greet(): print('Hi')`?
Exercise
Write a function called `is_even` that takes a number and returns `True` if it's even, `False` if it's odd. Then test it with the number 10.
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