os.path — Common pathname manipulations (2024)

Source code: Lib/genericpath.py, Lib/posixpath.py (for POSIX) andLib/ntpath.py (for Windows).

This module implements some useful functions on pathnames. To read or writefiles see open(), and for accessing the filesystem see the osmodule. The path parameters can be passed as strings, or bytes, or any objectimplementing the os.PathLike protocol.

Unlike a Unix shell, Python does not do any automatic path expansions.Functions such as expanduser() and expandvars() can be invokedexplicitly when an application desires shell-like path expansion. (See alsothe 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 astheir parameters. The result is an object of the same type, if a path orfile name is returned.

Note

Since different operating systems have different path name conventions, thereare several versions of this module in the standard library. Theos.path module is always the path module suitable for the operatingsystem Python is running on, and therefore usable for local paths. However,you can also import and use the individual modules if you want to manipulatea path that is always in one of the different formats. They all have thesame interface:

  • posixpath for UNIX-style paths

  • ntpath for Windows paths

Changed in version 3.8: exists(), lexists(), isdir(), isfile(),islink(), and ismount() now return False instead ofraising an exception for paths that contain characters or bytesunrepresentable at the OS level.

os.path.abspath(path)

Return a normalized absolutized version of the pathname path. On mostplatforms, this is equivalent to calling the function normpath() asfollows: normpath(join(os.getcwd(), path)).

Changed in version 3.6: Accepts a path-like object.

os.path.basename(path)

Return the base name of pathname path. This is the second element of thepair returned by passing path to the function split(). Note thatthe result of this function is differentfrom the Unix basename program; where basename for'/foo/bar/' returns 'bar', the basename() function returns anempty string ('').

Changed in version 3.6: Accepts a path-like object.

os.path.commonpath(paths)

Return the longest common sub-path of each pathname in the iterablepaths. Raise ValueError if paths contain both absoluteand relative pathnames, if paths are on different drives, orif paths is empty. Unlike commonprefix(), this returns avalid path.

Added in version 3.5.

Changed in version 3.6: Accepts a sequence of path-like objects.

Changed in version 3.13: Any iterable can now be passed, rather than just sequences.

os.path.commonprefix(list)

Return the longest path prefix (taken character-by-character) that is aprefix of all paths in list. If list is empty, return the empty string('').

Note

This function may return invalid paths because it works acharacter at a time. To obtain a valid path, seecommonpath().

>>> os.path.commonprefix(['/usr/lib', '/usr/local/lib'])'/usr/l'>>> os.path.commonpath(['/usr/lib', '/usr/local/lib'])'/usr'

Changed in version 3.6: Accepts a path-like object.

os.path.dirname(path)

Return the directory name of pathname path. This is the first element ofthe pair returned by passing path to the function split().

Changed in version 3.6: Accepts a path-like object.

os.path.exists(path)

Return True if path refers to an existing path or an openfile descriptor. Returns False for broken symbolic links. Onsome platforms, this function may return False if permission isnot granted to execute os.stat() on the requested file, evenif 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, includingbroken symbolic links. Equivalent to exists() on platforms lackingos.lstat().

Changed in version 3.6: Accepts a path-like object.

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 HOMEif it is set; otherwise the current user’s home directory is looked up in thepassword directory through the built-in module pwd. An initial ~useris looked up directly in the password directory.

On Windows, USERPROFILE will be used if set, otherwise a combinationof HOMEPATH and HOMEDRIVE will be used. An initial~user is handled by checking that the last directory component of the currentuser’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 isreturned unchanged.

Changed in version 3.6: Accepts a path-like object.

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 variablename. Malformed variable names and references to non-existing variables areleft unchanged.

On Windows, %name% expansions are supported in addition to $name and${name}.

Changed in version 3.6: Accepts a path-like object.

os.path.getatime(path)

Return the time of last access of path. The return value is a floating-point number givingthe number of seconds since the epoch (see the time module). RaiseOSError 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 numbergiving the number of seconds since the epoch (see the time module).Raise OSError if the file does not exist or is inaccessible.

Changed in version 3.6: Accepts a path-like object.

os.path.getctime(path)

Return the system’s ctime which, on some systems (like Unix) is the time of thelast 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 (seethe time module). Raise OSError if the file does not exist oris inaccessible.

Changed in version 3.6: Accepts a path-like object.

os.path.getsize(path)

Return the size, in bytes, of path. Raise OSError if the file doesnot exist or is inaccessible.

Changed in version 3.6: Accepts a path-like object.

os.path.isabs(path)

Return True if path is an absolute pathname. On Unix, that means itbegins with a slash, on Windows that it begins with two (back)slashes, or adrive letter, colon, and (back)slash together.

Changed in version 3.6: Accepts a path-like object.

Changed in version 3.13: On Windows, returns False if the given path starts with exactly one(back)slash.

os.path.isfile(path)

Return True if path is an existing regular file.This follows symbolic links, so both islink() and isfile() canbe true for the same path.

Changed in version 3.6: Accepts a path-like object.

os.path.isdir(path)

Return True if path is an existing directory. Thisfollows symbolic links, so both islink() and isdir() can be truefor the same path.

Changed in version 3.6: Accepts a path-like object.

os.path.isjunction(path)

Return True if path refers to an existing directoryentry that is a junction. Always return False if junctions are notsupported on the current platform.

Added in version 3.12.

os.path.islink(path)

Return True if path refers to an existing directoryentry that is a symbolic link. Always False if symbolic links are notsupported by the Python runtime.

Changed in version 3.6: Accepts a path-like object.

os.path.ismount(path)

Return True if pathname path is a mount point: a point in afile system where a different file system has been mounted. On POSIX, thefunction checks whether path’s parent, path/.., is on a differentdevice than path, or whether path/.. and path point to the samei-node on the same device — this should detect mount points for all Unixand POSIX variants. It is not able to reliably detect bind mounts on thesame filesystem. On Windows, a drive letter root and a share UNC arealways mount points, and for any other path GetVolumePathName is calledto see if it is different from the input path.

Changed in version 3.4: Added support for detecting non-root mount points on Windows.

Changed in version 3.6: Accepts a path-like object.

os.path.isdevdrive(path)

Return True if pathname path is located on a Windows Dev Drive.A Dev Drive is optimized for developer scenarios, and offers fasterperformance for reading and writing files. It is recommended for use forsource code, temporary build directories, package caches, and otherIO-intensive operations.

May raise an error for an invalid path, for example, one without arecognizable drive, but returns False on platforms that do not supportDev Drives. See the Windows documentationfor information on enabling and creating Dev Drives.

Added in version 3.12.

Changed in version 3.13: The function is now available on all platforms, and will always return False on those that have no support for Dev Drives

os.path.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 Windowssystems. These rules change over time in various Windows releases.This function may be updated in future Python releases as changes tothe rules become broadly available.

Availability: Windows.

Added in version 3.13.

os.path.join(path, *paths)

Join one or more path segments intelligently. The return value is theconcatenation of path and all members of *paths, with exactly onedirectory 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 orends in a separator. If a segment is an absolute path (which on Windowsrequires both a drive and a root), then all previous segments are ignored andjoining continues from the absolute path segment.

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 anabsolute path, all previous segments are ignored and the drive is reset. Notethat since there is a current directory for each drive,os.path.join("c:", "foo") represents a path relative to the currentdirectory 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 thepathname to lowercase, and also convert forward slashes to backward slashes.On other operating systems, return the path unchanged.

Changed in version 3.6: Accepts a path-like object.

os.path.normpath(path)

Normalize a pathname by collapsing redundant separators and up-levelreferences so that A//B, A/B/, A/./B and A/foo/../B allbecome A/B. This string manipulation may change the meaning of a paththat contains symbolic links. On Windows, it converts forward slashes tobackward slashes. To normalize case, use normcase().

Note

On POSIX systems, in accordance with IEEE Std 1003.1 2013 Edition; 4.13Pathname Resolution,if a pathname begins with exactly two slashes, the first componentfollowing the leading characters may be interpreted in an implementation-definedmanner, although more than two leading characters shall be treated as asingle character.

Changed in version 3.6: Accepts a path-like object.

os.path.realpath(path, *, strict=False)

Return the canonical path of the specified filename, eliminating any symboliclinks encountered in the path (if they are supported by the operatingsystem). On Windows, this function will also resolve MS-DOS (also called 8.3)style names such as C:\\PROGRA~1 to C:\\Program Files.

If a path doesn’t exist or a symlink loop is encountered, and strict isTrue, OSError is raised. If strict is False these errorsare ignored, and so the result might be missing or otherwise inaccessible.

Note

This function emulates the operating system’s procedure for making a pathcanonical, which differs slightly between Windows and UNIX with respectto how links and subsequent path components interact.

Operating system APIs make paths canonical as needed, so it’s notnormally necessary to call this function.

Changed in version 3.6: Accepts a path-like object.

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 orfrom an optional start directory. This is a path computation: thefilesystem is not accessed to confirm the existence or nature of path orstart. On Windows, ValueError is raised when path and startare on different drives.

start defaults to os.curdir.

Changed in version 3.6: Accepts a path-like object.

os.path.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 anexception if an os.stat() call on either pathname fails.

Changed in version 3.2: Added Windows support.

Changed in version 3.4: Windows now uses the same implementation as all other platforms.

Changed in version 3.6: Accepts a path-like object.

os.path.sameopenfile(fp1, fp2)

Return True if the file descriptors fp1 and fp2 refer to the same file.

Changed in version 3.2: Added Windows support.

Changed in version 3.6: Accepts a path-like object.

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 theunderlying comparison used by samefile() and sameopenfile().

Changed in version 3.4: Added Windows support.

Changed in version 3.6: Accepts a path-like object.

os.path.split(path)

Split the pathname path into a pair, (head, tail) where tail is thelast pathname component and head is everything leading up to that. Thetail part will never contain a slash; if path ends in a slash, tailwill be empty. If there is no slash in path, head will be empty. Ifpath is empty, both head and tail are empty. Trailing slashes arestripped from head unless it is the root (one or more slashes only). Inall cases, join(head, tail) returns a path to the same location as path(but the strings may differ). Also see the functions dirname() andbasename().

Changed in version 3.6: Accepts a path-like object.

os.path.splitdrive(path)

Split the pathname path into a pair (drive, tail) where drive is eithera mount point or the empty string. On systems which do not use drivespecifications, 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 everythingup to and including the colon:

>>> splitdrive("c:/dir")("c:", "/dir")

If the path contains a UNC path, drive will contain the host nameand share:

>>> splitdrive("//host/computer/dir")("//host/computer", "/dir")

Changed in version 3.6: Accepts a path-like object.

os.path.splitroot(path)

Split the pathname path into a 3-item tuple (drive, root, tail) wheredrive is a device name or mount point, root is a string of separatorsafter the drive, and tail is everything after the root. Any of theseitems may be the empty string. In all cases, drive + root + tail willbe the same as path.

On POSIX systems, drive is always empty. The root may be empty (if path isrelative), a single forward slash (if path is absolute), or two forward slashes(implementation-defined per IEEE Std 1003.1-2017; 4.13 Pathname Resolution.)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 devicename. The root may be empty, a forward slash, or a backward slash. Forexample:

>>> splitroot('C:/Users/Sam')('C:', '/', 'Users/Sam')>>> splitroot('//Server/Share/Users/Sam')('//Server/Share', '/', 'Users/Sam')

Added in version 3.12.

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 atmost 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 tobe part of the root:

>>> splitext('.cshrc')('.cshrc', '')>>> splitext('/foo/....jpg')('/foo/....jpg', '')

Changed in version 3.6: Accepts a path-like object.

os.path.supports_unicode_filenames

True if arbitrary Unicode strings can be used as file names (within limitationsimposed by the file system).

os.path — Common pathname manipulations (2024)
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