11.2. "os.path" — manipulation courante des chemins
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**Code source :** Lib/posixpath.py (pour POSIX), Lib/ntpath.py (pour
Windows NT), et Lib/macpath.py (pour Macintosh)

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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" pour l'ancienne forme des chemins MacOS

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))`".

   Modifié dans la version 3.6: Accepte un *path-like object*.

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 ("''").

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepts a sequence of *path-like
   objects*.

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'

   Modifié dans la version 3.6: Accepte un *path-like object*.

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()".

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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()".

   Modifié dans la version 3.6: Accepte un *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
   "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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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}".

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

os.path.getsize(path)

   Return the size, in bytes, of *path*.  Raise "OSError" if the file
   does not exist or is inaccessible.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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".

   Modifié dans la version 3.6: Accepts a *path-like object* for
   *path* and *paths*.

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" (directly or indirectly through
   the "os.PathLike" interface).

   Modifié dans la version 3.6: Accepte un *path-like object*.

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()".

   Modifié dans la version 3.6: Accepte un *path-like object*.

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).

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *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 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.

   Modifié dans la version 3.6: Accepte un *path-like object*.

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.

   Modifié dans la version 3.6: Accepte un *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 the
   underlying comparison used by "samefile()" and "sameopenfile()".

   Disponibilité : Unix, Windows.

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

   Modifié dans la version 3.6: Accepte un *path-like object*.

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()".

   Modifié dans la version 3.6: Accepte un *path-like object*.

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")"

   Modifié dans la version 3.6: Accepte un *path-like object*.

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', '')".

   Modifié dans la version 3.6: Accepte un *path-like object*.

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).
