This book presumes some familiarity with Python 3 and general concepts of application development. We won’t look deeply at subtle or complex features of Python; we’ll avoid much consideration of the internals of the language.

We’ll presume some familiarity with functional programming. Since Python is not a functional programming language, we can’t dig deeply into functional concepts. We’ll pick and choose the aspects of functional programming that fit well with Python and leverage just those that seem useful.

Some of the examples use exploratory data analysis (EDA) as a problem domain to show the value of functional programming. Some familiarity with basic probability and statistics will help with this. There are only a few examples that move into more serious data science.

You’ll need to have Python 3.6 installed and running. For more information on Python, visit http://www.python.org/. The examples all make extensive use of type hints, which means that the latest version of mypy must be installed as well.

Check out https://pypi.python.org/pypi/mypy for the latest version of mypy.

Examples in Chapter 9, More Itertools Techniques, use PIL and Beautiful Soup 4. The Pillow fork of the original PIL library works nicely; refer to https://pypi.python.org/pypi/Pillow/2.7.0 and https://pypi.python.org/pypi/beautifulsoup4/4.6.0.

Examples in Chapter 14, The PyMonad Library, use PyMonad; check out https://pypi.python.org/pypi/PyMonad/1.3.

All of these packages should be installed using the following:

$ pip install pillow beautifulsoup4 PyMonad

You can download the example code files for this book from your account at www.packtpub.com. If you purchased this book elsewhere, you can visit www.packtpub.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packtpub.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Functional-Python-Programming-Second-Edition/. We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Python has other statements, such as global or nonlocal, which modify the rules for variables in a particular namespace."

A block of code is set as follows:

s = 0 
for n in range(1, 10): 
    if n % 3 == 0 or n % 5 == 0: 
        s += n 
print(s) 

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

s = 0 
for n in range(1, 10): 
    if n % 3 == 0 or n % 5 == 0: 
        s += n 
print(s) 

Any command-line input or output is written as follows:

$ pip install pillow beautifulsoup4 PyMonad

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "For our purposes, we will distinguish between only two of the many paradigms: functional programming and imperative programming."