1 2:mod:`linecache` --- Random access to text lines 3================================================ 4 5.. module:: linecache 6 :synopsis: This module provides random access to individual lines from text files. 7.. sectionauthor:: Moshe Zadka <moshez@zadka.site.co.il> 8 9**Source code:** :source:`Lib/linecache.py` 10 11-------------- 12 13The :mod:`linecache` module allows one to get any line from any file, while 14attempting to optimize internally, using a cache, the common case where many 15lines are read from a single file. This is used by the :mod:`traceback` module 16to retrieve source lines for inclusion in the formatted traceback. 17 18The :mod:`linecache` module defines the following functions: 19 20 21.. function:: getline(filename, lineno[, module_globals]) 22 23 Get line *lineno* from file named *filename*. This function will never raise an 24 exception --- it will return ``''`` on errors (the terminating newline character 25 will be included for lines that are found). 26 27 .. index:: triple: module; search; path 28 29 If a file named *filename* is not found, the function will look for it in the 30 module search path, ``sys.path``, after first checking for a :pep:`302` 31 ``__loader__`` in *module_globals*, in case the module was imported from a 32 zipfile or other non-filesystem import source. 33 34 .. versionadded:: 2.5 35 The *module_globals* parameter was added. 36 37 38.. function:: clearcache() 39 40 Clear the cache. Use this function if you no longer need lines from files 41 previously read using :func:`getline`. 42 43 44.. function:: checkcache([filename]) 45 46 Check the cache for validity. Use this function if files in the cache may have 47 changed on disk, and you require the updated version. If *filename* is omitted, 48 it will check all the entries in the cache. 49 50Example:: 51 52 >>> import linecache 53 >>> linecache.getline('/etc/passwd', 4) 54 'sys:x:3:3:sys:/dev:/bin/sh\n' 55 56