Conventions Used in This Book

The following conventions are used throughout this book.

Reference Conventions

In the function/method reference entries, when feasible, each optional parameter is shown with a default value using the Python syntax name=value. Built-in functions need not accept named parameters, so parameter names are not significant. Some optional parameters are best explained in terms of their presence or absence, rather than through default values. In such cases, a parameter is indicated as being optional by enclosing it in brackets ([ ]). When more than one argument is optional, the brackets are nested.

Typographic Conventions

Italic

Used for filenames, program names, URLs, and to introduce new terms.

Constant Width

Used for all code examples, as well as for commands and all items that appear in code, including keywords, methods, functions, classes, and modules.

Constant Width Italic

Used to show text that can be replaced with user-supplied values in code examples.

Constant Width Bold

Used for commands that must be typed on the command line, and occasionally for emphasis in code examples or to indicate code output.