Doc/library/os.path.rst
!os.path --- Common pathname manipulations.. module:: os.path :synopsis: Operations on pathnames.
Source code: :source:Lib/genericpath.py, :source:Lib/posixpath.py (for POSIX) and
:source:Lib/ntpath.py (for Windows).
.. 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 strings, or bytes, or any object
implementing the :class:os.PathLike protocol.
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.)
.. seealso::
The :mod: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
: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:
!posixpath for UNIX-style paths!ntpath for Windows paths.. versionchanged:: 3.8
:func:exists, :func:lexists, :func:isdir, :func:isfile,
:func:islink, and :func:ismount now return False instead of
raising an exception for paths that contain characters or bytes
unrepresentable at the OS level.
.. function:: abspath(path)
Return a normalized absolutized version of the pathname path. On most
platforms, this is equivalent to calling normpath(join(os.getcwd(), path)).
.. seealso:: :func:os.path.join and :func:os.path.normpath.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. 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 ('').
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: commonpath(paths)
Return the longest common sub-path of each pathname in the iterable
paths. Raise :exc:ValueError if paths contain both absolute
and relative pathnames, if paths are on different drives, or
if paths is empty. Unlike :func:commonprefix, this returns a
valid path.
.. versionadded:: 3.5
.. versionchanged:: 3.6
Accepts a sequence of :term:path-like objects <path-like object>.
.. versionchanged:: 3.13 Any iterable can now be passed, rather than just sequences.
.. function:: commonprefix(list, /)
Return the longest string prefix (taken character-by-character) that is a
prefix of all strings in list. If list is empty, return the empty string
('').
.. warning::
This function may return invalid paths because it works a
character at a time.
If you need a **common path prefix**, then the algorithm
implemented in this function is not secure. Use
:func:`commonpath` for finding a common path prefix.
::
>>> os.path.commonprefix(['/usr/lib', '/usr/local/lib'])
'/usr/l'
>>> os.path.commonpath(['/usr/lib', '/usr/local/lib'])
'/usr'
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. deprecated:: 3.15
Deprecated in favor of :func:os.path.commonpath for path prefixes.
The :func:os.path.commonprefix function is being deprecated due to
having a misleading name and module. The function is not safe to use for
path prefixes despite being included in a module about path manipulation,
meaning it is easy to accidentally introduce path traversal
vulnerabilities into Python programs by using this function.
.. 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.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. 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.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: lexists(path)
Return True if path refers to an existing path, including
broken symbolic links. Equivalent to :func:exists on platforms lacking
:func:os.lstat.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. index:: single: ~ (tilde); home directory expansion
.. 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:: pair: 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:USERPROFILE will be used if set, otherwise a combination
of :envvar:HOMEPATH and :envvar:HOMEDRIVE will be used. An initial
~user is handled by checking that the last directory component of the current
user's home directory matches :envvar: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.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. versionchanged:: 3.8
No longer uses :envvar:HOME on Windows.
.. index:: single: $ (dollar); environment variables expansion single: % (percent); environment variables expansion (Windows)
.. 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}.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: 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 :mod:time module). Raise
:exc:OSError if the file does not exist or is inaccessible.
.. function:: 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 :mod:time module).
Raise :exc:OSError if the file does not exist or is inaccessible.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. 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.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: getsize(path, /)
Return the size, in bytes, of path. Raise :exc:OSError if the file does
not exist or is inaccessible.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. 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 two (back)slashes, or a
drive letter, colon, and (back)slash together.
.. seealso:: :func:abspath
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. versionchanged:: 3.13
On Windows, returns False if the given path starts with exactly one
(back)slash.
.. function:: isfile(path)
Return True if path is an :func:existing <exists> regular file.
This follows symbolic links, so both :func:islink and :func:isfile can
be true for the same path.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: isdir(path, /)
Return True if path is an :func:existing <exists> directory. This
follows symbolic links, so both :func:islink and :func:isdir can be true
for the same path.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: isjunction(path)
Return True if path refers to an :func:existing <lexists> directory
entry that is a junction. Always return False if junctions are not
supported on the current platform.
.. versionadded:: 3.12
.. function:: islink(path)
Return True if path refers to an :func:existing <exists> directory
entry that is a symbolic link. Always False if symbolic links are not
supported by the Python runtime.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. 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. On POSIX, 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. It is not able to reliably detect bind mounts on the
same filesystem. On Linux systems, it will always return True for btrfs
subvolumes, even if they aren't mount points. 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.
.. versionchanged:: 3.4 Added support for detecting non-root mount points on Windows.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: isdevdrive(path)
Return True if pathname path is located on a Windows Dev Drive.
A Dev Drive is optimized for developer scenarios, and offers faster
performance for reading and writing files. It is recommended for use for
source code, temporary build directories, package caches, and other
IO-intensive operations.
May raise an error for an invalid path, for example, one without a
recognizable drive, but returns False on platforms that do not support
Dev Drives. See the Windows documentation <https://learn.microsoft.com/windows/dev-drive/>_
for information on enabling and creating Dev Drives.
.. versionadded:: 3.12
.. versionchanged:: 3.13
The function is now available on all platforms, and will always return False on those that have no support for Dev Drives
.. function:: isreserved(path)
Return True if path is a reserved pathname on the current system.
On Windows, reserved filenames include those that end with a space or dot;
those that contain colons (i.e. file streams such as "name:stream"),
wildcard characters (i.e. '*?"<>'), pipe, or ASCII control characters;
as well as DOS device names such as "NUL", "CON", "CONIN$", "CONOUT$",
"AUX", "PRN", "COM1", and "LPT1".
.. note::
This function approximates rules for reserved paths on most Windows
systems. These rules change over time in various Windows releases.
This function may be updated in future Python releases as changes to
the rules become broadly available.
.. availability:: Windows.
.. versionadded:: 3.13
.. function:: join(path, /, *paths)
Join one or more path segments intelligently. The return value is the concatenation of path and all members of *paths, with exactly one directory separator following each non-empty part, except the last. That is, the result will only end in a separator if the last part is either empty or ends in a separator.
If a segment is an absolute path (which on Windows requires both a drive and a root), then all previous segments are ignored and joining continues from the absolute path segment. On Linux, for example::
>>> os.path.join('/home/foo', 'bar')
'/home/foo/bar'
>>> os.path.join('/home/foo', '/home/bar')
'/home/bar'
On Windows, the drive is not reset when a rooted path segment (e.g.,
r'\foo') is encountered. If a segment is on a different drive or is an
absolute path, all previous segments are ignored and the drive is reset. For
example::
>>> os.path.join('c:\\', 'foo')
'c:\\foo'
>>> os.path.join('c:\\foo', 'd:\\bar')
'd:\\bar'
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 :file:C: (:file:c:foo), not :file:c:\\foo.
.. versionchanged:: 3.6
Accepts a :term:path-like object for path and paths.
.. function:: 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.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. 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.
.. note::
On POSIX systems, in accordance with IEEE Std 1003.1 2013 Edition; 4.13 Pathname Resolution <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13>_,
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.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: 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). On Windows, this function will also resolve MS-DOS (also called 8.3)
style names such as C:\\PROGRA~1 to C:\\Program Files.
By default, the path is evaluated up to the first component that does not
exist, is a symlink loop, or whose evaluation raises :exc:OSError.
All such components are appended unchanged to the existing part of the path.
Some errors that are handled this way include "access denied", "not a directory", or "bad argument to internal function". Thus, the resulting path may be missing or inaccessible, may still contain links or loops, and may traverse non-directories.
This behavior can be modified by keyword arguments:
If strict is True, the first error encountered when evaluating the path is
re-raised.
In particular, :exc:FileNotFoundError is raised if path does not exist,
or another :exc:OSError if it is otherwise inaccessible.
If strict is :data:ALL_BUT_LAST, the last component of the path
is allowed to be missing, but all other errors are raised.
If strict is :py:data:os.path.ALLOW_MISSING, errors other than
:exc:FileNotFoundError are re-raised (as with strict=True).
Thus, the returned path will not contain any symbolic links, but the named
file and some of its parent directories may be missing.
.. 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.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. versionchanged:: 3.8 Symbolic links and junctions are now resolved on Windows.
.. versionchanged:: 3.10 The strict parameter was added.
.. versionchanged:: 3.15
The :data:ALL_BUT_LAST and :data:ALLOW_MISSING values for
the strict parameter was added.
.. data:: ALL_BUT_LAST
Special value used for the strict argument in :func:realpath.
.. versionadded:: 3.15
.. data:: ALLOW_MISSING
Special value used for the strict argument in :func:realpath.
.. versionadded:: 3.15
.. function:: 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, :exc:ValueError is raised when path and start
are on different drives.
start defaults to :data:os.curdir.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: samefile(path1, 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 :func:os.stat call on either pathname fails.
.. versionchanged:: 3.2 Added Windows support.
.. versionchanged:: 3.4 Windows now uses the same implementation as all other platforms.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: sameopenfile(fp1, fp2)
Return True if the file descriptors fp1 and fp2 refer to the same file.
.. versionchanged:: 3.2 Added Windows support.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. 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.
.. versionchanged:: 3.4 Added Windows support.
.. 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:join,
:func:dirname and :func:basename.
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. 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
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::
>>> splitdrive("//host/computer/dir")
("//host/computer", "/dir")
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. function:: splitroot(path, /)
Split the pathname path into a 3-item tuple (drive, root, tail) where
drive is a device name or mount point, root is a string of separators
after the drive, and tail is everything after the root. Any of these
items may be the empty string. In all cases, drive + root + tail will
be the same as path.
On POSIX systems, drive is always empty. The root may be empty (if path is
relative), a single forward slash (if path is absolute), or two forward slashes
(implementation-defined per IEEE Std 1003.1-2017; 4.13 Pathname Resolution <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13>_.)
For example::
>>> splitroot('/home/sam')
('', '/', 'home/sam')
>>> splitroot('//home/sam')
('', '//', 'home/sam')
>>> splitroot('///home/sam')
('', '/', '//home/sam')
On Windows, drive may be empty, a drive-letter name, a UNC share, or a device name. The root may be empty, a forward slash, or a backward slash. For example::
>>> splitroot('C:/Users/Sam')
('C:', '/', 'Users/Sam')
>>> splitroot('//Server/Share/Users/Sam')
('//Server/Share', '/', 'Users/Sam')
.. versionadded:: 3.12
.. function:: 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', '')
.. versionchanged:: 3.6
Accepts a :term:path-like object.
.. data:: supports_unicode_filenames
True if arbitrary Unicode strings can be used as file names (within limitations
imposed by the file system).