174 lines
6.8 KiB
TeX
174 lines
6.8 KiB
TeX
\section{\module{os.path} ---
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Common pathname manipulations}
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\declaremodule{standard}{os.path}
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\modulesynopsis{Common pathname manipulations.}
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This module implements some useful functions on pathnames.
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\index{path!operations}
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\begin{funcdesc}{abspath}{path}
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Return a normalized absolutized version of the pathname \var{path}.
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On most platforms, this is equivalent to
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\code{normpath(join(os.getcwd()), \var{path})}.
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\end{funcdesc}
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\begin{funcdesc}{basename}{path}
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Return the base name of pathname \var{path}. This is the second half
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of the pair returned by \code{split(\var{path})}.
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\end{funcdesc}
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\begin{funcdesc}{commonprefix}{list}
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Return the longest string that is a prefix of all strings in
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\var{list}. If \var{list} is empty, return the empty string
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(\code{''}).
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\end{funcdesc}
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\begin{funcdesc}{dirname}{path}
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Return the directory name of pathname \var{path}. This is the first
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half of the pair returned by \code{split(\var{path})}.
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\end{funcdesc}
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\begin{funcdesc}{exists}{path}
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Return true if \var{path} refers to an existing path.
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\end{funcdesc}
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\begin{funcdesc}{expanduser}{path}
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Return the argument with an initial component of \samp{\~} or
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\samp{\~\var{user}} replaced by that \var{user}'s home directory. An
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initial \samp{\~{}} is replaced by the environment variable
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\envvar{HOME}; an initial \samp{\~\var{user}} is looked up in the
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password directory through the built-in module
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\refmodule{pwd}\refbimodindex{pwd}. If the expansion fails, or if the
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path does not begin with a tilde, the path is returned unchanged. On
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the Macintosh, this always returns \var{path} unchanged.
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\end{funcdesc}
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\begin{funcdesc}{expandvars}{path}
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Return the argument with environment variables expanded. Substrings
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of the form \samp{\$\var{name}} or \samp{\$\{\var{name}\}} are
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replaced by the value of environment variable \var{name}. Malformed
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variable names and references to non-existing variables are left
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unchanged. On the Macintosh, this always returns \var{path}
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unchanged.
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\end{funcdesc}
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\begin{funcdesc}{getsize}{path}
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Return the size, in bytes, of \var{filename}. Raise
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\exception{os.error} if the file does not exist or is inaccessible.
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\versionadded{1.5.2}
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\end{funcdesc}
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\begin{funcdesc}{getmtime}{path}
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Return the time of last modification of \var{filename}. The return
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value is integer giving the number of seconds since the epoch (see the
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\refmodule{time} module). Raise \exception{os.error} if the file does
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not exist or is inaccessible.
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\versionadded{1.5.2}
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\end{funcdesc}
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\begin{funcdesc}{getatime}{path}
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Return the time of last access of \var{filename}. The return
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value is integer giving the number of seconds since the epoch (see the
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\refmodule{time} module). Raise \exception{os.error} if the file does
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not exist or is inaccessible.
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\versionadded{1.5.2}
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\end{funcdesc}
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\begin{funcdesc}{isabs}{path}
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Return true if \var{path} is an absolute pathname (begins with a
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slash).
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\end{funcdesc}
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\begin{funcdesc}{isfile}{path}
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Return true if \var{path} is an existing regular file. This follows
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symbolic links, so both \function{islink()} and \function{isfile()}
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can be true for the same path.
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\end{funcdesc}
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\begin{funcdesc}{isdir}{path}
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Return true if \var{path} is an existing directory. This follows
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symbolic links, so both \function{islink()} and \function{isdir()} can
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be true for the same path.
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\end{funcdesc}
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\begin{funcdesc}{islink}{path}
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Return true if \var{path} refers to a directory entry that is a
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symbolic link. Always false if symbolic links are not supported.
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\end{funcdesc}
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\begin{funcdesc}{ismount}{path}
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Return true if pathname \var{path} is a \dfn{mount point}: a point in
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a file system where a different file system has been mounted. The
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function checks whether \var{path}'s parent, \file{\var{path}/..}, is
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on a different device than \var{path}, or whether \file{\var{path}/..}
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and \var{path} point to the same i-node on the same device --- this
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should detect mount points for all \UNIX{} and \POSIX{} variants.
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\end{funcdesc}
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\begin{funcdesc}{join}{path1\optional{, path2\optional{, ...}}}
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Joins one or more path components intelligently. If any component is
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an absolute path, all previous components are thrown away, and joining
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continues. The return value is the concatenation of \var{path1}, and
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optionally \var{path2}, etc., with exactly one slash (\code{'/'})
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inserted between components, unless \var{path} is empty.
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\end{funcdesc}
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\begin{funcdesc}{normcase}{path}
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Normalize the case of a pathname. On \UNIX{}, this returns the path
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unchanged; on case-insensitive filesystems, it converts the path to
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lowercase. On Windows, it also converts forward slashes to backward
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slashes.
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\end{funcdesc}
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\begin{funcdesc}{normpath}{path}
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Normalize a pathname. This collapses redundant separators and
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up-level references, e.g. \code{A//B}, \code{A/./B} and
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\code{A/foo/../B} all become \code{A/B}. It does not normalize the
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case (use \function{normcase()} for that). On Windows, it does
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converts forward slashes to backward slashes.
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\end{funcdesc}
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\begin{funcdesc}{samefile}{path1, path2}
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Return true if both pathname arguments refer to the same file or
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directory (as indicated by device number and i-node number).
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Raise an exception if a \function{os.stat()} call on either pathname
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fails.
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\end{funcdesc}
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\begin{funcdesc}{split}{path}
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Split the pathname \var{path} in a pair \code{(\var{head},
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\var{tail})}, where \var{tail} is the last pathname component and
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\var{head} is everything leading up to that. The \var{tail} part will
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never contain a slash; if \var{path} ends in a slash, \var{tail} will
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be empty. If there is no slash in \var{path}, \var{head} will be
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empty. If \var{path} is empty, both \var{head} and \var{tail} are
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empty. Trailing slashes are stripped from \var{head} unless it is the
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root (one or more slashes only). In nearly all cases,
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\code{join(\var{head}, \var{tail})} equals \var{path} (the only
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exception being when there were multiple slashes separating \var{head}
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from \var{tail}).
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\end{funcdesc}
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\begin{funcdesc}{splitext}{path}
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Split the pathname \var{path} in a pair \code{(\var{root}, \var{ext})}
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such that \code{\var{root} + \var{ext} == \var{path}},
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and \var{ext} is empty or begins with a period and contains
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at most one period.
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\end{funcdesc}
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\begin{funcdesc}{walk}{path, visit, arg}
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Calls the function \var{visit} with arguments
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\code{(\var{arg}, \var{dirname}, \var{names})} for each directory in the
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directory tree rooted at \var{path} (including \var{path} itself, if it
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is a directory). The argument \var{dirname} specifies the visited
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directory, the argument \var{names} lists the files in the directory
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(gotten from \code{os.listdir(\var{dirname})}).
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The \var{visit} function may modify \var{names} to
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influence the set of directories visited below \var{dirname}, e.g., to
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avoid visiting certain parts of the tree. (The object referred to by
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\var{names} must be modified in place, using \keyword{del} or slice
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assignment.)
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\end{funcdesc}
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