# 4. Functions¶

### Objectives¶

- Create custom functions.
- Import and use Python Standard Library modules, such as `random` and `math`, to reuse code and avoid “reinventing the wheel.”
- Pass data between functions.
- Generate a range of random numbers.

### Objectives (cont.)¶

- Learn simulation techniques using random-number generation.
- Seed the random number generator to ensure reproducibility.
- Pack values into a tuple and unpack values from a tuple.
- Return multiple values from a function via a tuple.
- Understand how an identifier’s scope determines where in your program you can use it.

### Objectives (cont.)¶

- Create functions with default parameter values.
- Call functions with keyword arguments.
- Create functions that can receive any number of arguments.
- Use methods of an object.

### Outline¶

- 4.1 Introduction
- 4.2 Defining Functions
- 4.3 Functions with Multiple Parameters
- 4.4 Random-Number Generation
- 4.5 Case Study: A Game of Chance
- 4.6 Python Standard Library
- 4.7 `math` Module Functions
- 4.8 Using IPython Tab Completion for Discovery
- 4.9 Default Parameter Values
- 4.10 Keyword Arguments
- 4.11 Arbitrary Argument Lists
- 4.12 Methods: Functions That Belong to Objects
- 4.13 Scope Rules
- 4.14 import: A Deeper Look
- 4.15 Passing Arguments to Functions: A Deeper Look
- 4.16 Function-Call Stack
- 4.17 Functional-Style Programming
- 4.18 Intro to Data Science: Measures of Dispersion
- 4.19 Wrap-Up
- Exercises

©1992–2020 by Pearson Education, Inc. All Rights Reserved. This content is based on Chapter 4 of the book Intro to Python for Computer Science and Data Science: Learning to Program with AI, Big Data and the Cloud.

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