Source code: Lib/posixpath.py [for POSIX] and Lib/ntpath.py [for Windows].
This module implements some useful functions on pathnames. To read or write files see open[]
, and for accessing the filesystem see the os
module. The path parameters can be passed as strings, or bytes, or any object implementing the os.PathLike
protocol.
Unlike
a Unix shell, Python does not do any automatic path expansions. Functions such as expanduser[]
and expandvars[]
can be invoked explicitly when an application desires shell-like path expansion. [See also the
glob
module.]
See also
The pathlib
module offers high-level path objects.
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 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:
posixpath
for UNIX-style pathsntpath
for Windows paths
Changed in version 3.8: exists[]
,
lexists[]
, isdir[]
, isfile[]
, islink[]
,
and ismount[]
now return False
instead of raising an exception for paths that contain characters or bytes unrepresentable at the OS level.
os.path.
abspath
[path]¶
Return a normalized absolutized version of the pathname path. On most platforms, this is equivalent to calling the function normpath[]
as follows: normpath[join[os.getcwd[], path]]
.
os.path.
basename
[path]¶Return the base name of pathname path. This is the second element of the pair returned by passing path to the function split[]
.
Note that the result of this function is different from the Unix basename program; where basename for '/foo/bar/'
returns 'bar'
, the basename[]
function returns an empty string [''
].
os.path.
commonpath
[paths]¶Return the longest common sub-path of each pathname in the sequence paths. Raise ValueError
if paths contain both absolute and
relative pathnames, the paths are on the different drives or if paths is empty. Unlike commonprefix[]
, this returns a valid path.
Availability: Unix, Windows.
New in version 3.5.
os.path.
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
This function may return invalid paths because it works a
character at a time. To obtain a valid path, see commonpath[]
.
>>> os.path.commonprefix[['/usr/lib', '/usr/local/lib']] '/usr/l' >>> os.path.commonpath[['/usr/lib', '/usr/local/lib']] '/usr'
os.path.
dirname
[path]¶Return the directory name of pathname
path. This is the first element of the pair returned by passing path to the function split[]
.
os.path.
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 os.stat[]
on the requested file, even if the path physically exists.
Changed in version 3.3: path can now be an integer: True
is returned if it is an open
file descriptor, False
otherwise.
os.path.
lexists
[path]¶Return True
if path refers to an existing path. Returns True
for broken symbolic links. Equivalent to exists[]
on platforms lacking os.lstat[]
.
os.path.
expanduser
[path]¶On Unix and Windows, return the argument with
an initial component of ~
or ~user
replaced by that user’s home directory.
On Unix, an initial ~
is replaced by the environment variable HOME
if it is set; otherwise the current user’s home directory is looked up in the password directory through the built-in module
pwd
. An initial ~user
is looked up directly in the password directory.
On Windows, USERPROFILE
will be used if set, otherwise a combination of HOMEPATH
and HOMEDRIVE
will be used. An initial ~user
is handled by checking that the last
directory component of the current user’s home directory matches USERNAME
, and replacing it if so.
If the expansion fails or if the path does not begin with a tilde, the path is returned unchanged.
Changed in version 3.8: No longer uses HOME
on Windows.
os.path.
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}
.
os.path.
getatime
[path]¶Return the time of last access of path. The return value is a floating point number giving the number of seconds since the epoch [see the
time
module]. Raise OSError
if the file does not exist or is inaccessible.
os.path.
getmtime
[path]¶Return the time of last modification of path. The return value is a floating point number giving the number of seconds since the epoch [see the time
module]. Raise OSError
if the file does not exist or is inaccessible.
os.path.
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 time
module]. Raise OSError
if the file
does not exist or is inaccessible.
os.path.
getsize
[path]¶Return the size, in bytes, of path. Raise OSError
if the file does not exist or is
inaccessible.
os.path.
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.
os.path.
isfile
[path]¶Return True
if path is an existing
regular file. This follows symbolic links, so both
islink[]
and isfile[]
can be true for the same path.
os.path.
isdir
[path]¶Return True
if path is an existing
directory. This follows symbolic links, so both
islink[]
and isdir[]
can be true for the same path.
os.path.
islink
[path]¶Return True
if path refers to an existing
directory entry that is a symbolic link. Always False
if symbolic links are not supported
by the Python runtime.
os.path.
ismount
[path]¶Return True
if pathname path is a mount point: a point in a file system where a different file system has been mounted. On POSIX, the function checks whether path’s parent, path/..
, is on a
different device than path, or whether path/..
and path point to the same i-node on the same device — this should detect mount points for all Unix and POSIX variants. It is not able to reliably detect bind mounts on the same filesystem. On Windows, a drive letter root and a share UNC are always mount points, and for any other path GetVolumePathName
is called to see if it is different from the input path.
New in version 3.4: Support for detecting non-root mount points on Windows.
os.path.
join
[path, *paths]¶Join one or more path components intelligently. The return value is the concatenation of path and any members of *paths with exactly one directory separator following each non-empty part except the last, meaning that the result will only end in a separator if the last part is empty. If a component is an absolute path, all previous components are thrown away and joining continues from the absolute path component.
On Windows, the drive letter is not reset when an absolute path component [e.g., r'\foo'
] is encountered. If a component contains a drive letter, all previous components are thrown away and the drive letter is reset. Note that since there is a
current directory for each drive, os.path.join["c:", "foo"]
represents a path relative to the current directory on drive C:
[c:foo
], not c:\foo
.
Changed in version 3.6: Accepts a path-like object for path and paths.
os.path.
normcase
[path]¶Normalize the case of a pathname. On Windows, convert all characters in the pathname to lowercase, and also convert forward slashes to backward slashes. On other operating systems, return the path unchanged.
os.path.
normpath
[path]¶Normalize a pathname by collapsing redundant separators and up-level references so that
A//B
,A/B/
,A/./B
andA/foo/../B
all becomeA/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, usenormcase[]
.
Note
On POSIX systems, in accordance with IEEE Std 1003.1 2013 Edition; 4.13 Pathname Resolution, if a pathname begins with exactly two slashes, the first component following the leading characters may be interpreted in an implementation-defined manner, although more than two leading characters shall be treated as a single character.
os.path.
realpath
[path, *,
strict=False]¶Return the canonical path of the specified filename, eliminating any symbolic links encountered in the path [if they are supported by the operating system].
If a path doesn’t exist or a symlink loop is encountered, and strict is True
,
OSError
is raised. If strict is False
, the path is resolved as far as possible and any remainder is appended without checking whether it exists.
Note
This function emulates the operating system’s procedure for making a path canonical, which differs slightly between Windows and UNIX with respect to how links and subsequent path components interact.
Operating system APIs make paths canonical as needed, so it’s not normally necessary to call this function.
Changed in version 3.8: Symbolic links and junctions are now resolved on Windows.
Changed in version 3.10: The strict parameter was added.
os.path.
relpath
[path,
start=os.curdir]¶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. On Windows,
ValueError
is raised when path and start are on different drives.
start defaults to os.curdir
.
Availability: Unix, Windows.
os.path.
samefile
[path2, path2]¶Return True
if both pathname arguments refer to the same file or directory. This is determined by the device number and i-node number and raises an exception if an
os.stat[]
call on either pathname fails.
Availability: Unix, Windows.
Changed in version 3.2: Added Windows support.
Changed in version 3.4: Windows now uses the same implementation as all other platforms.
os.path.
sameopenfile
[fp1, fp2]¶Return True
if the file descriptors fp1 and fp2 refer to the same file.
Availability: Unix, Windows.
Changed in version 3.2: Added Windows support.
os.path.
samestat
[stat1, stat2]¶Return True
if the stat tuples stat1 and stat2 refer to the same file. These structures may have been returned by
os.fstat[]
, os.lstat[]
, or os.stat[]
. This function implements the underlying comparison used by
samefile[]
and sameopenfile[]
.
Availability: Unix, Windows.
Changed in version 3.4: Added Windows support.
os.path.
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
dirname[]
and basename[]
.
os.path.
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:
>>> splitdrive["c:/dir"] ["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:
>>> splitdrive["//host/computer/dir"] ["//host/computer", "/dir"]
os.path.
splitext
[path]¶Split the pathname path into a pair [root, ext]
such that root + ext ==
path
, and the extension, ext, is empty or begins with a period and contains at most one period.
If the path contains no extension, ext will be ''
:
>>> splitext['bar'] ['bar', '']
If the path contains an extension, then ext will be set to this extension, including the leading period. Note that previous periods will be ignored:
>>> splitext['foo.bar.exe'] ['foo.bar', '.exe'] >>> splitext['/foo/bar.exe'] ['/foo/bar', '.exe']
Leading periods of the last component of the path are considered to be part of the root:
>>> splitext['.cshrc'] ['.cshrc', ''] >>> splitext['/foo/....jpg'] ['/foo/....jpg', '']
os.path.
supports_unicode_filenames
¶True
if arbitrary Unicode strings can be used as file names [within limitations imposed by the file system].