程式扎記: [Python Std Library] File and Directory Access : linecache — Random access to text lines

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2012年5月13日 星期日

[Python Std Library] File and Directory Access : linecache — Random access to text lines


來源自 這裡
Preface :
This 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 traceback module to retrieve source lines for inclusion in the formatted traceback.

Supported APIs :
This API defines the following functions :
linecache.getline(filename, lineno[, module_globals])
New in version 2.5: The module_globals parameter was added.
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).

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.
>>> import linecache
>>> linecache.getline('/etc/passwd', 4)
'sys:x:3:3:sys:/dev:/bin/sh\n'

linecache.clearcache()
Clear the cache. Use this function if you no longer need lines from files previously read using getline().

linecache.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.


Supplement :
29.5. runpy — Locating and executing Python modules
This module is used to locate and run Python modules without importing them first...
This message was edited 6 times. Last update was at 14/05/2012 09:06:59

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