1 :mod:`pydoc` --- Documentation generator and online help system 2 =============================================================== 3 4 .. module:: pydoc 5 :synopsis: Documentation generator and online help system. 6 .. moduleauthor:: Ka-Ping Yee <ping (a] lfw.org> 7 .. sectionauthor:: Ka-Ping Yee <ping (a] lfw.org> 8 9 10 .. versionadded:: 2.1 11 12 .. index:: 13 single: documentation; generation 14 single: documentation; online 15 single: help; online 16 17 **Source code:** :source:`Lib/pydoc.py` 18 19 -------------- 20 21 The :mod:`pydoc` module automatically generates documentation from Python 22 modules. The documentation can be presented as pages of text on the console, 23 served to a Web browser, or saved to HTML files. 24 25 For modules, classes, functions and methods, the displayed documentation is 26 derived from the docstring (i.e. the :attr:`__doc__` attribute) of the object, 27 and recursively of its documentable members. If there is no docstring, 28 :mod:`pydoc` tries to obtain a description from the block of comment lines just 29 above the definition of the class, function or method in the source file, or at 30 the top of the module (see :func:`inspect.getcomments`). 31 32 The built-in function :func:`help` invokes the online help system in the 33 interactive interpreter, which uses :mod:`pydoc` to generate its documentation 34 as text on the console. The same text documentation can also be viewed from 35 outside the Python interpreter by running :program:`pydoc` as a script at the 36 operating system's command prompt. For example, running :: 37 38 pydoc sys 39 40 at a shell prompt will display documentation on the :mod:`sys` module, in a 41 style similar to the manual pages shown by the Unix :program:`man` command. The 42 argument to :program:`pydoc` can be the name of a function, module, or package, 43 or a dotted reference to a class, method, or function within a module or module 44 in a package. If the argument to :program:`pydoc` looks like a path (that is, 45 it contains the path separator for your operating system, such as a slash in 46 Unix), and refers to an existing Python source file, then documentation is 47 produced for that file. 48 49 .. note:: 50 51 In order to find objects and their documentation, :mod:`pydoc` imports the 52 module(s) to be documented. Therefore, any code on module level will be 53 executed on that occasion. Use an ``if __name__ == '__main__':`` guard to 54 only execute code when a file is invoked as a script and not just imported. 55 56 When printing output to the console, :program:`pydoc` attempts to paginate the 57 output for easier reading. If the :envvar:`PAGER` environment variable is set, 58 :program:`pydoc` will use its value as a pagination program. 59 60 Specifying a ``-w`` flag before the argument will cause HTML documentation 61 to be written out to a file in the current directory, instead of displaying text 62 on the console. 63 64 Specifying a ``-k`` flag before the argument will search the synopsis 65 lines of all available modules for the keyword given as the argument, again in a 66 manner similar to the Unix :program:`man` command. The synopsis line of a 67 module is the first line of its documentation string. 68 69 You can also use :program:`pydoc` to start an HTTP server on the local machine 70 that will serve documentation to visiting Web browsers. :program:`pydoc -p 1234` 71 will start a HTTP server on port 1234, allowing you to browse 72 the documentation at ``http://localhost:1234/`` in your preferred Web browser. 73 :program:`pydoc -g` will start the server and additionally bring up a 74 small :mod:`Tkinter`\ -based graphical interface to help you search for 75 documentation pages. 76 77 When :program:`pydoc` generates documentation, it uses the current environment 78 and path to locate modules. Thus, invoking :program:`pydoc spam` 79 documents precisely the version of the module you would get if you started the 80 Python interpreter and typed ``import spam``. 81 82 Module docs for core modules are assumed to reside in 83 https://docs.python.org/library/. This can be overridden by setting the 84 :envvar:`PYTHONDOCS` environment variable to a different URL or to a local 85 directory containing the Library Reference Manual pages. 86 87
