| :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. The path parameters can be passed as either strings, |
| or bytes. Applications are encouraged to represent file names as |
| (Unicode) character strings. Unfortunately, some file names may not be |
| representable as strings on Unix, so applications that need to support |
| arbitrary file names on Unix should use bytes objects to represent |
| path names. Vice versa, using bytes objects cannot represent all file |
| names on Windows (in the standard ``mbcs`` encoding), hence Windows |
| applications should use string objects to access all files. |
| |
| Unlike a unix shell, Python does not do any *automatic* path expansions. |
| Functions such as :func:`expanduser` and :func:`expandvars` can be invoked |
| explicitly when an application desires shell-like path expansion. (See also |
| the :mod:`glob` module.) |
| |
| .. note:: |
| |
| All of these functions accept either only bytes or only string objects as |
| their parameters. The result is an object of the same type, if a path or |
| file name is returned. |
| |
| |
| .. note:: |
| |
| Since different operating systems have different path name conventions, there |
| are several versions of this module in the standard library. The |
| :mod:`os.path` module is always the path module suitable for the operating |
| system Python is running on, and therefore usable for local paths. However, |
| you can also import and use the individual modules if you want to manipulate |
| a path that is *always* in one of the different formats. They all have the |
| same interface: |
| |
| * :mod:`posixpath` for UNIX-style paths |
| * :mod:`ntpath` for Windows paths |
| * :mod:`macpath` for old-style MacOS paths |
| * :mod:`os2emxpath` for OS/2 EMX paths |
| |
| |
| .. function:: abspath(path) |
| |
| Return a normalized absolutized version of the pathname *path*. On most |
| platforms, this is equivalent to calling the function :func:`normpath` as |
| follows: ``normpath(join(os.getcwd(), path))``. |
| |
| |
| .. function:: basename(path) |
| |
| Return the base name of pathname *path*. This is the second element of the |
| pair returned by passing *path* to the function :func:`split`. 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 element of |
| the pair returned by passing *path* to the function :func:`split`. |
| |
| |
| .. function:: exists(path) |
| |
| Return ``True`` if *path* refers to an existing path or an open |
| file descriptor. 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. |
| |
| .. versionchanged:: 3.3 |
| *path* can now be an integer: ``True`` is returned if it is an |
| open file descriptor, ``False`` otherwise. |
| |
| |
| .. 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:`OSError` 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:`OSError` 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 metadata 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:`OSError` if the file does not exist or |
| is inaccessible. |
| |
| |
| .. function:: getsize(path) |
| |
| Return the size, in bytes, of *path*. Raise :exc:`OSError` 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``) following each non-empty part except the last. |
| (This means that an empty last part will result in a path that ends with a |
| separator.) 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 and Mac OS X, 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. |
| Raise a TypeError if the type of *path* is not ``str`` or ``bytes``. |
| |
| |
| .. function:: normpath(path) |
| |
| Normalize a pathname by collapsing redundant separators and up-level |
| references so that ``A//B``, ``A/B/``, ``A/./B`` and ``A/foo/../B`` all |
| become ``A/B``. This string manipulation may change the meaning of a path |
| that contains symbolic links. On Windows, it converts forward slashes to |
| backward slashes. To normalize case, use :func:`normcase`. |
| |
| |
| .. 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=None) |
| |
| Return a relative filepath to *path* either from the current directory or |
| from an optional *start* directory. This is a path computation: the |
| filesystem is not accessed to confirm the existence or nature of *path* or |
| *start*. |
| |
| *start* defaults to :attr:`os.curdir`. |
| |
| Availability: Unix, Windows. |
| |
| |
| .. function:: samefile(path1, path2) |
| |
| Return ``True`` if both pathname arguments refer to the same file or directory. |
| On Unix, this is determined by the device number and i-node number and raises an |
| exception if a :func:`os.stat` call on either pathname fails. |
| |
| On Windows, two files are the same if they resolve to the same final path |
| name using the Windows API call GetFinalPathNameByHandle. This function |
| raises an exception if handles cannot be obtained to either file. |
| |
| Availability: Unix, Windows. |
| |
| .. versionchanged:: 3.2 |
| Added Windows support. |
| |
| |
| .. function:: sameopenfile(fp1, fp2) |
| |
| Return ``True`` if the file descriptors *fp1* and *fp2* refer to the same file. |
| |
| Availability: Unix, Windows. |
| |
| .. versionchanged:: 3.2 |
| Added Windows support. |
| |
| |
| .. 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:`os.fstat`, |
| :func:`os.lstat`, or :func:`os.stat`. This function implements the |
| underlying comparison used by :func:`samefile` and :func:`sameopenfile`. |
| |
| Availability: 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 |
| all cases, ``join(head, tail)`` returns a path to the same location as *path* |
| (but the strings may differ). Also see the functions :func:`dirname` and |
| :func:`basename`. |
| |
| |
| .. function:: splitdrive(path) |
| |
| Split the pathname *path* into a pair ``(drive, tail)`` where *drive* is either |
| a mount point 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*. |
| |
| On Windows, splits a pathname into drive/UNC sharepoint and relative path. |
| |
| If the path contains a drive letter, drive will contain everything |
| up to and including the colon. |
| e.g. ``splitdrive("c:/dir")`` returns ``("c:", "/dir")`` |
| |
| If the path contains a UNC path, drive will contain the host name |
| and share, up to but not including the fourth separator. |
| e.g. ``splitdrive("//host/computer/dir")`` returns ``("//host/computer", "/dir")`` |
| |
| |
| .. 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) |
| |
| .. deprecated:: 3.1 |
| Use *splitdrive* instead. |
| |
| 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. |
| |
| |
| .. data:: supports_unicode_filenames |
| |
| ``True`` if arbitrary Unicode strings can be used as file names (within limitations |
| imposed by the file system). |