Defining functions

A function is a named block of code you can run again whenever you need it.

• Start it with def, a name, brackets and a colon.
• The indented lines are the body; they run only when you call the function.
• Call it with its name and brackets: greet().

def greet():
    print("Namaste!")

greet()
greet()

Namaste!
Namaste!

Remember: Defining a function doesn't run it. Calling it does.

Common mistake: Calling a function before its def line. Python reads top to bottom, so it isn't defined yet.