1. Python Pocket Reference Introduction Book Conventions
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Python Pocket Reference by Mark Lutz
Python Pocket Reference Table of Contents
Python Pocket Reference Introduction
Updated for both Python 3.4 and 2.7, this convenient pocket guide is the perfect on-the-job quick reference. You’ll find concise, need-to-know information on Python types and statements, special method names, built-in functions and exceptions, commonly used standard library modules, and other prominent Python tools. The handy index lets you pinpoint exactly what you need.
Written by Mark Lutz—widely recognized as the world’s leading Python trainer—Python Pocket Reference is an ideal companion to O’Reilly’s classic Python tutorials, Learning Python and Programming Python, also written by Mark.
This fifth edition covers:
Built-in object types, including numbers, lists, dictionaries, and more Statements and syntax for creating and processing objects Functions and modules for structuring and reusing code Python’s object-oriented programming tools Built-in functions, exceptions, and attributes Special operator overloading methods Widely used standard library modules and extensions Command-line options and development tools Python idioms and hints The Python SQL Database API
Python Pocket Reference
Mark Lutz
Chapter 1. Python Pocket Reference
Introduction
Python is a general-purpose, multiparadigm, open source computer programming language, with support for object-oriented, functional, and procedural coding structures. It is commonly used both for standalone programs and for scripting applications in a wide variety of domains, and is generally considered to be one of the most widely used programming languages in the world.
Among Python’s features are an emphasis on code readability and library functionality, and a design that optimizes developer productivity, software quality, program portability, and component integration. Python programs run on most platforms in common use, including Unix and Linux, Windows and Macintosh, Java and .NET, Android and iOS, and more.
This pocket reference summarizes Python types and statements, special method names, built-in functions and exceptions, commonly used standard library modules, and other prominent Python tools. It is intended to serve as a concise reference tool for developers and is designed to be a companion to other books that provide tutorials, code examples, and other learning materials.
This fifth edition covers both Python 3.X and 2.X. It focuses primarily on 3.X, but also documents differences in 2.X along the way. Specifically, this edition has been updated to be current with Python versions 3.3 and 2.7 as well as prominent enhancements in the imminent 3.4 release, although most of its content also applies both to earlier and to later releases in the 3.X and 2.X lines.
This edition also applies to all major implementations of Python — including CPython, PyPy, Jython, IronPython, and Stackless — and has been updated and expanded for recent changes in language, libraries, and practice. Its changes include new coverage of the MRO and super(); formal algorithms of inheritance, imports, context managers, and block indentation; and commonly used library modules and tools, including json, timeit, random, subprocess, enum, and the new Windows launcher.
Book Conventions
The following notational conventions are used in this book:
[]
In syntax formats, items in brackets are optional; brackets are also used literally in some parts of Python’s syntax as noted where applicable (e.g., lists).
In syntax formats, items followed by an asterisk can be repeated zero or more times; star is also used literally in some parts of Python’s syntax (e.g., multiplication).
a | b
In syntax formats, items separated by a bar are alternatives; bar is also used literally in some parts of Python’s syntax (e.g., union).
Italic
Used for filenames and URLs, and to highlight new or important terms.
Constant width
Used for code, commands, and command-line options, and to indicate the names of modules, functions, attributes, variables, and methods.
Constant width italic
Used for replaceable parameter names in the syntax of command lines, expressions, functions, and methods.
Function()
Except where noted, callable functions and methods are denoted by trailing parentheses, to distinguish them from other types of attributes.
See “Section Header Name”
References to other sections in this book are given by section header text in double quotes.
Note
In this book, “3.X” and “2.X” mean that a topic applies to all commonly used releases in a Python line. More specific release numbers are used for topics of more limited scope (e.g., “2.7” means 2.7 only). Because future Python changes can invalidate applicability to future releases, also see Python’s “What’s New” documents, currently maintained at http://docs.python.org/3/whatsnew/index.html for Pythons released after this book.