Edit File: linecache.txt
:mod:`linecache` --- Random access to text lines ================================================ .. module:: linecache :synopsis: This module provides random access to individual lines from text files. .. sectionauthor:: Moshe Zadka <moshez@zadka.site.co.il> **Source code:** :source:`Lib/linecache.py` -------------- The :mod:`linecache` module allows one to get any line from any file, while attempting to optimize internally, using a cache, the common case where many lines are read from a single file. This is used by the :mod:`traceback` module to retrieve source lines for inclusion in the formatted traceback. The :mod:`linecache` module defines the following functions: .. function:: getline(filename, lineno[, module_globals]) Get line *lineno* from file named *filename*. This function will never raise an exception --- it will return ``''`` on errors (the terminating newline character will be included for lines that are found). .. index:: triple: module; search; path If a file named *filename* is not found, the function will look for it in the module search path, ``sys.path``, after first checking for a :pep:`302` ``__loader__`` in *module_globals*, in case the module was imported from a zipfile or other non-filesystem import source. .. versionadded:: 2.5 The *module_globals* parameter was added. .. function:: clearcache() Clear the cache. Use this function if you no longer need lines from files previously read using :func:`getline`. .. function:: checkcache([filename]) Check the cache for validity. Use this function if files in the cache may have changed on disk, and you require the updated version. If *filename* is omitted, it will check all the entries in the cache. Example:: >>> import linecache >>> linecache.getline('/etc/passwd', 4) 'sys:x:3:3:sys:/dev:/bin/sh\n'