4. Functions

We’ve seen a lot of code by now that makes use of functions. print(), len(), input(), and just about anything else we’ve written with parentheses ( ) after a name – these have all been functions. So, intuitively, you probably have a sense that when we write one of these function names in our code, we are telling the computer to do whatever it is that the given function does.

There’s always more detail underneath, though, and now is a good time to learn about the details of functions.

• 4.1. Function Calls
  • 4.1.1. Using Return Values
• 4.2. Built-In Functions
  • 4.2.1. Math Functions
  • 4.2.2. Random Numbers
  • 4.2.3. Other Modules
• 4.3. Function Definitions
  • 4.3.1. Flow of Execution
  • 4.3.2. Parameters and Arguments
  • 4.3.3. Fruitful Functions and Void Functions
  • 4.3.4. Why Define Functions?
• 4.4. Glossary