1 

     2 .. _library-intro:

     3 

     4 ************

     5 Introduction

     6 ************

     7 

     8 The "Python library" contains several different kinds of components.

     9 

    10 It contains data types that would normally be considered part of the "core" of a

    11 language, such as numbers and lists.  For these types, the Python language core

    12 defines the form of literals and places some constraints on their semantics, but

    13 does not fully define the semantics.  (On the other hand, the language core does

    14 define syntactic properties like the spelling and priorities of operators.)

    15 

    16 The library also contains built-in functions and exceptions --- objects that can

    17 be used by all Python code without the need of an :keyword:`import` statement.

    18 Some of these are defined by the core language, but many are not essential for

    19 the core semantics and are only described here.

    20 

    21 The bulk of the library, however, consists of a collection of modules. There are

    22 many ways to dissect this collection.  Some modules are written in C and built

    23 in to the Python interpreter; others are written in Python and imported in

    24 source form.  Some modules provide interfaces that are highly specific to

    25 Python, like printing a stack trace; some provide interfaces that are specific

    26 to particular operating systems, such as access to specific hardware; others

    27 provide interfaces that are specific to a particular application domain, like

    28 the World Wide Web. Some modules are available in all versions and ports of

    29 Python; others are only available when the underlying system supports or

    30 requires them; yet others are available only when a particular configuration

    31 option was chosen at the time when Python was compiled and installed.

    32 

    33 This manual is organized "from the inside out:" it first describes the built-in

    34 data types, then the built-in functions and exceptions, and finally the modules,

    35 grouped in chapters of related modules.  The ordering of the chapters as well as

    36 the ordering of the modules within each chapter is roughly from most relevant to

    37 least important.

    38 

    39 This means that if you start reading this manual from the start, and skip to the

    40 next chapter when you get bored, you will get a reasonable overview of the

    41 available modules and application areas that are supported by the Python

    42 library.  Of course, you don't *have* to read it like a novel --- you can also

    43 browse the table of contents (in front of the manual), or look for a specific

    44 function, module or term in the index (in the back).  And finally, if you enjoy

    45 learning about random subjects, you choose a random page number (see module

    46 :mod:`random`) and read a section or two.  Regardless of the order in which you

    47 read the sections of this manual, it helps to start with chapter :ref:`builtin`,

    48 as the remainder of the manual assumes familiarity with this material.

    49 

    50 Let the show begin!

    51