137 lines
4.7 KiB
TeX
137 lines
4.7 KiB
TeX
\section{Standard Module \sectcode{posixpath}}
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\stmodindex{posixpath}
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This module implements some useful functions on POSIX pathnames.
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\renewcommand{\indexsubitem}{(in module posixpath)}
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\begin{funcdesc}{basename}{p}
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Return the base name of pathname
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\var{p}.
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This is the second half of the pair returned by
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\code{posixpath.split(\var{p})}.
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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}.
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If
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\var{list}
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is empty, return the empty string (\code{''}).
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\end{funcdesc}
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\begin{funcdesc}{exists}{p}
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Return true if
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\var{p}
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refers to an existing path.
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\end{funcdesc}
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\begin{funcdesc}{expanduser}{p}
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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 \code{\${}HOME};
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an initial \samp{\~\var{user}} is looked up in the password directory through
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the built-in module \code{pwd}. If the expansion fails, or if the
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path does not begin with a tilde, the path is returned unchanged.
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\end{funcdesc}
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\begin{funcdesc}{expandvars}{p}
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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.
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\end{funcdesc}
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\begin{funcdesc}{isabs}{p}
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Return true if \var{p} is an absolute pathname (begins with a slash).
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\end{funcdesc}
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\begin{funcdesc}{isfile}{p}
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Return true if \var{p} is an existing regular file. This follows
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symbolic links, so both islink() and isfile() can be true for the same
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path.
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\end{funcdesc}
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\begin{funcdesc}{isdir}{p}
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Return true if \var{p} is an existing directory. This follows
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symbolic links, so both islink() and isdir() can be true for the same
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path.
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\end{funcdesc}
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\begin{funcdesc}{islink}{p}
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Return true if
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\var{p}
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refers to a directory entry that is a symbolic link.
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Always false if symbolic links are not supported.
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\end{funcdesc}
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\begin{funcdesc}{ismount}{p}
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Return true if \var{p} is a mount point. (This currently checks whether
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\code{\var{p}/..} is on a different device from \var{p} or whether
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\code{\var{p}/..} and \var{p} point to the same i-node on the same
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device --- is this test correct for all \UNIX{} and POSIX variants?)
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\end{funcdesc}
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\begin{funcdesc}{join}{p\, q}
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Join the paths
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\var{p}
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and
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\var{q} intelligently:
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If
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\var{q}
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is an absolute path, the return value is
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\var{q}.
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Otherwise, the concatenation of
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\var{p}
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and
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\var{q}
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is returned, with a slash (\code{'/'}) inserted unless
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\var{p}
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is empty or ends in a slash.
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\end{funcdesc}
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\begin{funcdesc}{normcase}{p}
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Normalize the case of a pathname. This returns the path unchanged;
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however, a similar function in \code{macpath} converts upper case to
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lower case.
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\end{funcdesc}
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\begin{funcdesc}{samefile}{p\, q}
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Return true if both pathname arguments refer to the same file or directory
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(as indicated by device number and i-node number).
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Raise an exception if a stat call on either pathname fails.
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\end{funcdesc}
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\begin{funcdesc}{split}{p}
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Split the pathname \var{p} in a pair \code{(\var{head}, \var{tail})}, where
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\var{tail} is the last pathname component and \var{head} is
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everything leading up to that. If \var{p} ends in a slash (except if
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it is the root), the trailing slash is removed and the operation
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applied to the result; otherwise, \code{join(\var{head}, \var{tail})} equals
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\var{p}. The \var{tail} part never contains a slash. Some boundary
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cases: if \var{p} is the root, \var{head} equals \var{p} and
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\var{tail} is empty; if \var{p} is empty, both \var{head} and
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\var{tail} are empty; if \var{p} contains no slash, \var{head} is
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empty and \var{tail} equals \var{p}.
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\end{funcdesc}
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\begin{funcdesc}{splitext}{p}
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Split the pathname \var{p} in a pair \code{(\var{root}, \var{ext})}
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such that \code{\var{root} + \var{ext} == \var{p}},
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the last component of \var{root} contains no periods,
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and \var{ext} is empty or begins with a period.
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\end{funcdesc}
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\begin{funcdesc}{walk}{p\, 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{p} (including \var{p} itself, if it is a
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directory). The argument \var{dirname} specifies the visited directory,
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the argument \var{names} lists the files in the directory (gotten from
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\code{posix.listdir(\var{dirname})}). The \var{visit} function may
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modify \var{names} to influence the set of directories visited below
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\var{dirname}, e.g., to avoid visiting certain parts of the tree. (The
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object referred to by \var{names} must be modified in place, using
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\code{del} or slice assignment.)
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\end{funcdesc}
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