Language Basics

A programming language involves two closely interleaved topics. On one hand, there are the statement constructs that process information inside the computer, with visible effects on the various external devices. On the other hand are the various types of data and relationship structures for organizing the information manipluated by the program.

This part describes the most commonly-used Python statements, sticking with basic numeric data types. Part II, “Data Structures” will present a reasonably complete set of built-in data types and features for Python. While the two are tightly interwoven, we pick the statements as more fundamental because we we can (and will) add new data types. Indeed, the essential thrust of object-oriented programming (covered in Part III, “Data + Processing = Objects”) is the creation of new data types.

Some of the examples in this part refer to the rules of various common casino games. Knowledge of casino gambling is not essential to understanding the language or this part of the book. We don't endorse casino gambling. Indeed, many of the exercises reveal the magnitude of the house edge in most casino games. However, casino games have just the right level of algorithmic complexity to make for excellent programming exercises.

In Chapter 3, Getting Started we'll describe the basics of computer programming, installing a Python interpreter, using Python interactively, and writing simple scripts. In Chapter 4, Simple Numeric Expressions and Output we'll introduce the print statement, and arithmetic expressions including the numeric data types, operators, conversions, and some built-in functions. We'll expand on this in Chapter 5, Advanced Expressions. We'll introduce variables, the assignment statement, and input in Chapter 6, Variables, Assignment and Input, allowing us to create simple input-process-output programs. When we add truth, comparisons, conditional processing, iterative processing and assertions in Chapter 7, Truth, Comparison and Conditional Processing, we'll have all the tools necessary for programming. In Chapter 9, Functions and Chapter 10, Additional Notes On Functions, we'll show how to define and use functions, the first of many tools for organizing programs to make them understandable.