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python-3.7.4-docs-html/_sources/library/intro.rst.txt

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+.. _library-intro:
+
+************
+Introduction
+************
+
+The "Python library" contains several different kinds of components.
+
+It contains data types that would normally be considered part of the "core" of a
+language, such as numbers and lists.  For these types, the Python language core
+defines the form of literals and places some constraints on their semantics, but
+does not fully define the semantics.  (On the other hand, the language core does
+define syntactic properties like the spelling and priorities of operators.)
+
+The library also contains built-in functions and exceptions --- objects that can
+be used by all Python code without the need of an :keyword:`import` statement.
+Some of these are defined by the core language, but many are not essential for
+the core semantics and are only described here.
+
+The bulk of the library, however, consists of a collection of modules. There are
+many ways to dissect this collection.  Some modules are written in C and built
+in to the Python interpreter; others are written in Python and imported in
+source form.  Some modules provide interfaces that are highly specific to
+Python, like printing a stack trace; some provide interfaces that are specific
+to particular operating systems, such as access to specific hardware; others
+provide interfaces that are specific to a particular application domain, like
+the World Wide Web. Some modules are available in all versions and ports of
+Python; others are only available when the underlying system supports or
+requires them; yet others are available only when a particular configuration
+option was chosen at the time when Python was compiled and installed.
+
+This manual is organized "from the inside out:" it first describes the built-in
+functions, data types and exceptions, and finally the modules, grouped in
+chapters of related modules.
+
+This means that if you start reading this manual from the start, and skip to the
+next chapter when you get bored, you will get a reasonable overview of the
+available modules and application areas that are supported by the Python
+library.  Of course, you don't *have* to read it like a novel --- you can also
+browse the table of contents (in front of the manual), or look for a specific
+function, module or term in the index (in the back).  And finally, if you enjoy
+learning about random subjects, you choose a random page number (see module
+:mod:`random`) and read a section or two.  Regardless of the order in which you
+read the sections of this manual, it helps to start with chapter
+:ref:`built-in-funcs`, as the remainder of the manual assumes familiarity with
+this material.
+
+Let the show begin!
+
+
+.. _availability:
+
+Notes on availability
+=====================
+
+* An "Availability: Unix" note means that this function is commonly found on
+  Unix systems.  It does not make any claims about its existence on a specific
+  operating system.
+
+* If not separately noted, all functions that claim "Availability: Unix" are
+  supported on Mac OS X, which builds on a Unix core.
+