| |
| :mod:`os.path` --- Common pathname manipulations |
| ================================================ |
| |
| .. module:: os.path |
| :synopsis: Operations on pathnames. |
| |
| |
| .. index:: single: path; operations |
| |
| This module implements some useful functions on pathnames. To read or |
| write files see :func:`open`, and for accessing the filesystem see the |
| :mod:`os` module. |
| |
| .. warning:: |
| |
| On Windows, many of these functions do not properly support UNC pathnames. |
| :func:`splitunc` and :func:`ismount` do handle them correctly. |
| |
| |
| .. function:: abspath(path) |
| |
| Return a normalized absolutized version of the pathname *path*. On most |
| platforms, this is equivalent to ``normpath(join(os.getcwd(), path))``. |
| |
| |
| .. function:: basename(path) |
| |
| Return the base name of pathname *path*. This is the second half of the pair |
| returned by ``split(path)``. Note that the result of this function is different |
| from the Unix :program:`basename` program; where :program:`basename` for |
| ``'/foo/bar/'`` returns ``'bar'``, the :func:`basename` function returns an |
| empty string (``''``). |
| |
| |
| .. function:: commonprefix(list) |
| |
| Return the longest path prefix (taken character-by-character) that is a prefix |
| of all paths in *list*. If *list* is empty, return the empty string (``''``). |
| Note that this may return invalid paths because it works a character at a time. |
| |
| |
| .. function:: dirname(path) |
| |
| Return the directory name of pathname *path*. This is the first half of the |
| pair returned by ``split(path)``. |
| |
| |
| .. function:: exists(path) |
| |
| Return ``True`` if *path* refers to an existing path. Returns ``False`` for |
| broken symbolic links. On some platforms, this function may return ``False`` if |
| permission is not granted to execute :func:`os.stat` on the requested file, even |
| if the *path* physically exists. |
| |
| |
| .. function:: lexists(path) |
| |
| Return ``True`` if *path* refers to an existing path. Returns ``True`` for |
| broken symbolic links. Equivalent to :func:`exists` on platforms lacking |
| :func:`os.lstat`. |
| |
| |
| .. function:: expanduser(path) |
| |
| On Unix and Windows, return the argument with an initial component of ``~`` or |
| ``~user`` replaced by that *user*'s home directory. |
| |
| .. index:: module: pwd |
| |
| On Unix, an initial ``~`` is replaced by the environment variable :envvar:`HOME` |
| if it is set; otherwise the current user's home directory is looked up in the |
| password directory through the built-in module :mod:`pwd`. An initial ``~user`` |
| is looked up directly in the password directory. |
| |
| On Windows, :envvar:`HOME` and :envvar:`USERPROFILE` will be used if set, |
| otherwise a combination of :envvar:`HOMEPATH` and :envvar:`HOMEDRIVE` will be |
| used. An initial ``~user`` is handled by stripping the last directory component |
| from the created user path derived above. |
| |
| If the expansion fails or if the path does not begin with a tilde, the path is |
| returned unchanged. |
| |
| |
| .. function:: expandvars(path) |
| |
| Return the argument with environment variables expanded. Substrings of the form |
| ``$name`` or ``${name}`` are replaced by the value of environment variable |
| *name*. Malformed variable names and references to non-existing variables are |
| left unchanged. |
| |
| On Windows, ``%name%`` expansions are supported in addition to ``$name`` and |
| ``${name}``. |
| |
| |
| .. function:: getatime(path) |
| |
| Return the time of last access of *path*. The return value is a number giving |
| the number of seconds since the epoch (see the :mod:`time` module). Raise |
| :exc:`os.error` if the file does not exist or is inaccessible. |
| |
| If :func:`os.stat_float_times` returns True, the result is a floating point |
| number. |
| |
| |
| .. function:: getmtime(path) |
| |
| Return the time of last modification of *path*. The return value is a number |
| giving the number of seconds since the epoch (see the :mod:`time` module). |
| Raise :exc:`os.error` if the file does not exist or is inaccessible. |
| |
| If :func:`os.stat_float_times` returns True, the result is a floating point |
| number. |
| |
| |
| .. function:: getctime(path) |
| |
| Return the system's ctime which, on some systems (like Unix) is the time of the |
| last change, and, on others (like Windows), is the creation time for *path*. |
| The return value is a number giving the number of seconds since the epoch (see |
| the :mod:`time` module). Raise :exc:`os.error` if the file does not exist or |
| is inaccessible. |
| |
| |
| .. function:: getsize(path) |
| |
| Return the size, in bytes, of *path*. Raise :exc:`os.error` if the file does |
| not exist or is inaccessible. |
| |
| |
| .. function:: isabs(path) |
| |
| Return ``True`` if *path* is an absolute pathname. On Unix, that means it |
| begins with a slash, on Windows that it begins with a (back)slash after chopping |
| off a potential drive letter. |
| |
| |
| .. function:: isfile(path) |
| |
| Return ``True`` if *path* is an existing regular file. This follows symbolic |
| links, so both :func:`islink` and :func:`isfile` can be true for the same path. |
| |
| |
| .. function:: isdir(path) |
| |
| Return ``True`` if *path* is an existing directory. This follows symbolic |
| links, so both :func:`islink` and :func:`isdir` can be true for the same path. |
| |
| |
| .. function:: islink(path) |
| |
| Return ``True`` if *path* refers to a directory entry that is a symbolic link. |
| Always ``False`` if symbolic links are not supported. |
| |
| |
| .. function:: ismount(path) |
| |
| Return ``True`` if pathname *path* is a :dfn:`mount point`: a point in a file |
| system where a different file system has been mounted. The function checks |
| whether *path*'s parent, :file:`path/..`, is on a different device than *path*, |
| or whether :file:`path/..` and *path* point to the same i-node on the same |
| device --- this should detect mount points for all Unix and POSIX variants. |
| |
| |
| .. function:: join(path1[, path2[, ...]]) |
| |
| Join one or more path components intelligently. If any component is an absolute |
| path, all previous components (on Windows, including the previous drive letter, |
| if there was one) are thrown away, and joining continues. The return value is |
| the concatenation of *path1*, and optionally *path2*, etc., with exactly one |
| directory separator (``os.sep``) inserted between components, unless *path2* is |
| empty. Note that on Windows, since there is a current directory for each drive, |
| ``os.path.join("c:", "foo")`` represents a path relative to the current |
| directory on drive :file:`C:` (:file:`c:foo`), not :file:`c:\\foo`. |
| |
| |
| .. function:: normcase(path) |
| |
| Normalize the case of a pathname. On Unix, this returns the path unchanged; on |
| case-insensitive filesystems, it converts the path to lowercase. On Windows, it |
| also converts forward slashes to backward slashes. |
| |
| |
| .. function:: normpath(path) |
| |
| Normalize a pathname. This collapses redundant separators and up-level |
| references so that ``A//B``, ``A/./B`` and ``A/foo/../B`` all become ``A/B``. |
| It does not normalize the case (use :func:`normcase` for that). On Windows, it |
| converts forward slashes to backward slashes. It should be understood that this |
| may change the meaning of the path if it contains symbolic links! |
| |
| |
| .. function:: realpath(path) |
| |
| Return the canonical path of the specified filename, eliminating any symbolic |
| links encountered in the path (if they are supported by the operating system). |
| |
| |
| .. function:: relpath(path[, start]) |
| |
| Return a relative filepath to *path* either from the current directory or from |
| an optional *start* point. |
| |
| *start* defaults to :attr:`os.curdir`. Availability: Windows, Unix. |
| |
| |
| .. function:: samefile(path1, path2) |
| |
| Return ``True`` if both pathname arguments refer to the same file or directory |
| (as indicated by device number and i-node number). Raise an exception if a |
| :func:`os.stat` call on either pathname fails. Availability: Macintosh, Unix. |
| |
| |
| .. function:: sameopenfile(fp1, fp2) |
| |
| Return ``True`` if the file descriptors *fp1* and *fp2* refer to the same file. |
| Availability: Macintosh, Unix. |
| |
| |
| .. function:: samestat(stat1, stat2) |
| |
| Return ``True`` if the stat tuples *stat1* and *stat2* refer to the same file. |
| These structures may have been returned by :func:`fstat`, :func:`lstat`, or |
| :func:`stat`. This function implements the underlying comparison used by |
| :func:`samefile` and :func:`sameopenfile`. Availability: Macintosh, Unix. |
| |
| |
| .. function:: split(path) |
| |
| Split the pathname *path* into a pair, ``(head, tail)`` where *tail* is the last |
| pathname component and *head* is everything leading up to that. The *tail* part |
| will never contain a slash; if *path* ends in a slash, *tail* will be empty. If |
| there is no slash in *path*, *head* will be empty. If *path* is empty, both |
| *head* and *tail* are empty. Trailing slashes are stripped from *head* unless |
| it is the root (one or more slashes only). In nearly all cases, ``join(head, |
| tail)`` equals *path* (the only exception being when there were multiple slashes |
| separating *head* from *tail*). |
| |
| |
| .. function:: splitdrive(path) |
| |
| Split the pathname *path* into a pair ``(drive, tail)`` where *drive* is either |
| a drive specification or the empty string. On systems which do not use drive |
| specifications, *drive* will always be the empty string. In all cases, ``drive |
| + tail`` will be the same as *path*. |
| |
| |
| .. function:: splitext(path) |
| |
| Split the pathname *path* into a pair ``(root, ext)`` such that ``root + ext == |
| path``, and *ext* is empty or begins with a period and contains at most one |
| period. Leading periods on the basename are ignored; ``splitext('.cshrc')`` |
| returns ``('.cshrc', '')``. |
| |
| |
| .. function:: splitunc(path) |
| |
| Split the pathname *path* into a pair ``(unc, rest)`` so that *unc* is the UNC |
| mount point (such as ``r'\\host\mount'``), if present, and *rest* the rest of |
| the path (such as ``r'\path\file.ext'``). For paths containing drive letters, |
| *unc* will always be the empty string. Availability: Windows. |
| |
| |
| .. function:: walk(path, visit, arg) |
| |
| Calls the function *visit* with arguments ``(arg, dirname, names)`` for each |
| directory in the directory tree rooted at *path* (including *path* itself, if it |
| is a directory). The argument *dirname* specifies the visited directory, the |
| argument *names* lists the files in the directory (gotten from |
| ``os.listdir(dirname)``). The *visit* function may modify *names* to influence |
| the set of directories visited below *dirname*, e.g. to avoid visiting certain |
| parts of the tree. (The object referred to by *names* must be modified in |
| place, using :keyword:`del` or slice assignment.) |
| |
| .. note:: |
| |
| Symbolic links to directories are not treated as subdirectories, and that |
| :func:`walk` therefore will not visit them. To visit linked directories you must |
| identify them with ``os.path.islink(file)`` and ``os.path.isdir(file)``, and |
| invoke :func:`walk` as necessary. |
| |
| .. note:: |
| |
| The newer :func:`os.walk` :term:`generator` supplies similar functionality |
| and can be easier to use. |
| |
| |
| .. data:: supports_unicode_filenames |
| |
| True if arbitrary Unicode strings can be used as file names (within limitations |
| imposed by the file system), and if :func:`os.listdir` returns Unicode strings |
| for a Unicode argument. |