10.1. os.path
— Common pathname manipulations¶
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 either strings,
or bytes. Applications are encouraged to represent file names as
(Unicode) character strings. Unfortunately, some file names may not be
representable as strings on Unix, so applications that need to support
arbitrary file names on Unix should use bytes objects to represent
path names. Vice versa, using bytes objects cannot represent all file
names on Windows (in the standard mbcs
encoding), hence Windows
applications should use string objects to access all files.
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 pathsmacpath
for old-style MacOS pathsos2emxpath
for OS/2 EMX paths
-
os.path.
abspath
(path)¶ Return a normalized absolutized version of the pathname path. On most platforms, this is equivalent to
normpath(join(os.getcwd(), path))
.
-
os.path.
basename
(path)¶ Return the base name of pathname path. This is the second half of the pair returned by
split(path)
. Note that the result of this function is different from the Unix basename program; where basename for'/foo/bar/'
returns'bar'
, thebasename()
function returns an empty string (''
).
-
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 that this may return invalid paths because it works a character at a time.
-
os.path.
dirname
(path)¶ Return the directory name of pathname path. This is the first half of the pair returned by
split(path)
.
-
os.path.
exists
(path)¶ Return
True
if path refers to an existing path. ReturnsFalse
for broken symbolic links. On some platforms, this function may returnFalse
if permission is not granted to executeos.stat()
on the requested file, even if the path physically exists.
-
os.path.
lexists
(path)¶ Return
True
if path refers to an existing path. ReturnsTrue
for broken symbolic links. Equivalent toexists()
on platforms lackingos.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 variableHOME
if it is set; otherwise the current user’s home directory is looked up in the password directory through the built-in modulepwd
. An initial~user
is looked up directly in the password directory.On Windows,
HOME
andUSERPROFILE
will be used if set, otherwise a combination ofHOMEPATH
andHOMEDRIVE
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). Raiseos.error
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). Raiseos.error
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 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). Raiseos.error
if the file does not exist or is inaccessible.
-
os.path.
getsize
(path)¶ Return the size, in bytes, of path. Raise
os.error
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 bothislink()
andisfile()
can be true for the same path.
-
os.path.
isdir
(path)¶ Return
True
if path is an existing directory. This follows symbolic links, so bothislink()
andisdir()
can be true for the same path.
-
os.path.
islink
(path)¶ Return
True
if path refers to a directory entry that is a symbolic link. AlwaysFalse
if symbolic links are not supported.
-
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. The function checks whether path‘s parent,path/..
, is on a different device than path, or whetherpath/..
and path point to the same i-node on the same device — this should detect mount points for all Unix and POSIX variants.
-
os.path.
join
(path1[, path2[, ...]])¶ Join one or more path components intelligently. If any component is an absolute path, all previous components (on Windows, including the previous drive letter, if there was one) are thrown away, and joining continues. The return value is the concatenation of path1, and optionally path2, etc., with exactly one directory separator (
os.sep
) following each non-empty part except the last. (This means that an empty last part will result in a path that ends with a separator.) Note that on Windows, since there is a current directory for each drive,os.path.join("c:", "foo")
represents a path relative to the current directory on driveC:
(c:foo
), notc:\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
orbytes
.
-
os.path.
normpath
(path)¶ Normalize a pathname. This collapses redundant separators and up-level references so that
A//B
,A/B/
,A/./B
andA/foo/../B
all becomeA/B
.It does not normalize the case (use
normcase()
for that). On Windows, it converts forward slashes to backward slashes. It should be understood that this may change the meaning of the path if it contains symbolic links!
-
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=None)¶ Return a relative filepath to path either from the current directory or from an optional start point.
start defaults to
os.curdir
.Availability: Unix, Windows.
-
os.path.
samefile
(path1, path2)¶ Return
True
if both pathname arguments refer to the same file or directory. On Unix, this is determined by the device number and i-node number and raises an exception if aos.stat()
call on either pathname fails.On Windows, two files are the same if they resolve to the same final path name using the Windows API call GetFinalPathNameByHandle. This function raises an exception if handles cannot be obtained to either file.
Availability: Unix, Windows.
Changed in version 3.2:
Changed in version 3.2: Added Windows support.
-
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:
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 byfstat()
,lstat()
, orstat()
. This function implements the underlying comparison used bysamefile()
andsameopenfile()
.Availability: Unix.
-
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).
-
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 thatroot + 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)¶ Deprecated since version 3.1:
Deprecated since 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.
Availability: Windows.
-
os.path.
supports_unicode_filenames
¶ True if arbitrary Unicode strings can be used as file names (within limitations imposed by the file system).