1.9 Functions

1.9 Functions

After this unit you will: package a task into a reusable function and understand where variables live.

Key points

• A parameter is the name in the definition; an argument is the value passed at call time.
• Default parameter: def power(base, exp=2).
• *args collects extra positional arguments into a tuple; **kwargs collects keyword arguments into a dict.
• lambda x: x ** 2 is a one-line anonymous function.
• Assigning inside a function creates a new local variable; to change an outer variable you must declare it global.