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