Python Pocket Reference

Major Built-in Modules

Built-in modules are always available, but must be imported to be used in clients. Either use “import module” and qualify names (“module.name”), or “from module import...” and use names unqualified (“name”). There are dozens of built-in modules; the next sections document the most commonly used.

The sys Module

Contains interpreter-specific exports.

argv

Command-line argument strings list: [command, arguments . . . ]. Like C’s “argv” array.

builtin_module_names

List of names of C modules compiled into this Python.

exc_info( )

Returns tuple of three values describing the exception currently being handled: (type, value, traceback). Specific to current thread. Subsumes exc_type, exc_value, and exc_traceback in Python 1.5 and later.

exc_type

Type of exception being handled (when an exception has been raised). Not thread-specific.

exc_value

Exception’s parameter (second argument to raise). Not thread-specific.

exc_traceback

Exception’s traceback object. Not thread-specific.

exec_prefix

Assign a string giving the site-specific directory prefix where the platform-dependent Python files are installed; defaults to “/usr/local,” or a build-time argument. Used to locate shared library modules (in <exec_ prefix>/lib/python<version >/lib-dynload ), and configuration files.

executable

File pathname of Python interperter.

exit(N)

Exits from python process with status N, by raising SystemExit (can be caught in a try and ignored).

exitfunc

Assign a no-argument function to be called on exits.

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