11.2. os.path — manipulation courante des chemins

Source code: Lib/posixpath.py (for POSIX), Lib/ntpath.py (for Windows NT), and Lib/macpath.py (for Macintosh)

Ce module implémente certaines fonctions utiles sur le nom des chemins. Pour lire ou écrire des fichiers, voir open(), et pour accéder au système de fichier, voir le module os. Les paramètres de chemin d’accès peuvent être passés sous forme de chaînes de caractères ou de chaîne d’octets. Les programmes sont encouragés à représenter les noms de fichiers en tant que chaînes de caractères Unicode. Malheureusement, certains noms de fichiers peuvent ne pas être représentés sous forme de chaînes de caractères sous UNIX, ainsi, les programmes qui doivent prendre en charge les noms de fichiers arbitraires sur UNIX doivent utiliser des chaînes d’octets pour représenter leurs chemins d’accès. Inversement, l’utilisation de chaîne d’octets ne peut pas représenter tous les noms de fichiers sous Windows (dans le codage mbcs standard), par conséquent les applications Windows doivent utiliser des chaînes de caractères Unicode pour accéder à tous les fichiers.

Contrairement à une invite de commandes Unix, Python ne fait aucune extension de chemin automatique. Des fonctions telles que expanduser() et expandvars() peuvent être appelées explicitement lorsqu’une application souhaite une extension de chemin semblable à celui d’une invite de commande (voir aussi le module glob).

Voir aussi

Le module pathlib offre une représentation objet de haut niveau des chemins.

Note

Toutes ces fonctions n’acceptent que des chaînes d’octets ou des chaînes de caractères en tant que paramètres. Le résultat est un objet du même type si un chemin ou un nom de fichier est renvoyé.

Note

Comme les différents systèmes d’exploitation ont des conventions de noms de chemins différentes, il existe plusieurs versions de ce module dans la bibliothèque standard. Le module os.path est toujours le module de chemin adapté au système d’exploitation sur lequel Python tourne, et donc adapté pour les chemins locaux. Cependant, vous pouvez également importer et utiliser les modules individuels si vous voulez manipuler un chemin qui est toujours dans l’un des différents formats. Ils ont tous la même interface :

  • posixpath pour les chemins de type UNIX
  • ntpath pour les chemins Windows
  • macpath for old-style MacOS paths
os.path.abspath(path)

Renvoie une version absolue et normalisée du chemin d’accès path. Sur la plupart des plates-formes, cela équivaut à appeler la fonction normpath() comme suit : normpath(join(os.getcwd(), chemin))`.

os.path.basename(path)

Renvoie le nom de base du chemin d’accès path. C’est le second élément de la paire renvoyée en passant path à la fonction split(). Notez que le résultat de cette fonction est différent de celui du programme Unix basename ; là où basename pour '/foo/bar/' renvoie 'bar', la fonction basename() renvoie une chaîne vide ('').

os.path.commonpath(paths)

Return the longest common sub-path of each pathname in the sequence paths. Raise ValueError if paths contains both absolute and relative pathnames, or if paths is empty. Unlike commonprefix(), this returns a valid path.

Disponibilité Unix, Windows

Nouveau dans la 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.

Modifié dans la 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, HOME and USERPROFILE will be used if set, otherwise a combination of HOMEPATH and 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.

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 number giving the number of seconds since the epoch (see the time module). Raise OSError if the file does not exist or is inaccessible.

If os.stat_float_times() returns True, the result is a floating point number.

os.path.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 time module). Raise OSError if the file does not exist or is inaccessible.

If os.stat_float_times() returns True, the result is a floating point number.

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.

Return True if path refers to a 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. 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.

Nouveau dans la 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 (os.sep) 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.

os.path.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.

os.path.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 normcase().

os.path.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).

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.

start defaults to os.curdir.

Disponibilité : Unix, Windows.

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

Disponibilité : Unix, Windows.

Modifié dans la version 3.2: Prise en charge de Windows.

Modifié dans la 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.

Disponibilité : Unix, Windows.

Modifié dans la version 3.2: Prise en charge de Windows.

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().

Disponibilité : Unix, Windows.

Modifié dans la version 3.4: Prise en charge de Windows.

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. 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")

os.path.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', '').

os.path.splitunc(path)

Obsolète depuis la version 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.

Disponibilité : Windows.

os.path.supports_unicode_filenames

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