os.path --- 常见路径名操作

源代码: Lib/posixpath.py (用于 POSIX)和 Lib/ntpath.py (用于 Windows NT)


该模块在路径名上实现了一些有用的功能:如需读取或写入文件,请参见 open() ;有关访问文件系统的信息,请参见 os 模块。路径参数可以字符串或字节形式传递。我们鼓励应用程序将文件名表示为(Unicode)字符串。不幸的是,某些文件名在Unix上可能无法用字符串表示,因此在Unix上平台上需要支持任意文件名的应用程序,应使用字节对象来表示路径名。反之亦然,在Windows平台上仅使用字节对象,不能表示的所有文件名(以标准 mbcs 编码),因此Windows应用程序应使用字符串对象来访问所有文件。

与unix shell不同,Python不执行任何 自动 路径扩展。当应用程序需要类似shell的路径扩展时,可以显式调用诸如 expanduser()expandvars() 之类的函数。 (另请参见 glob 模块。)

参见

pathlib 模块提供高级路径对象。

注解

所有这些函数都仅接受字节或字符串对象作为其参数。如果返回路径或文件名,则结果是相同类型的对象。

注解

由于不同的操作系统具有不同的路径名称约定,因此标准库中有此模块的几个版本。 os.path 模块始终是适合Python运行的操作系统的路径模块,因此可用于本地路径。但是,如果操作的路径 总是 以一种不同的格式显示,那么也可以分别导入和使用各个模块。它们都具有相同的界面:

  • posixpath 用于Unix 样式的路径

  • ntpath 用于 Windows 路径

在 3.8 版更改: exists(), lexists(), isdir(), isfile(), islink(), 和 ismount() 现在返回 False ,而不是对包含在操作系统级别不可表示的字符或字节的路径引发异常。

os.path.abspath(path)

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

在 3.6 版更改: 接受一个 类路径对象

os.path.basename(path)

Return the base name of pathname path. This is the second element of the pair returned by passing path to the function split(). Note that the result of this function is different from the Unix basename program; where basename for '/foo/bar/' returns 'bar', the basename() function returns an empty string ('').

在 3.6 版更改: 接受一个 类路径对象

os.path.commonpath(paths)

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

可用性: Unix, Windows。

3.5 新版功能.

在 3.6 版更改: 接受一个 类路径对象 序列。

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 ('').

注解

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'

在 3.6 版更改: 接受一个 类路径对象

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().

在 3.6 版更改: 接受一个 类路径对象

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.

在 3.3 版更改: path can now be an integer: True is returned if it is an open file descriptor, False otherwise.

在 3.6 版更改: 接受一个 类路径对象

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().

在 3.6 版更改: 接受一个 类路径对象

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, 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.

在 3.6 版更改: 接受一个 类路径对象

在 3.8 版更改: Windows 不再使用 HOME

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}.

在 3.6 版更改: 接受一个 类路径对象

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

在 3.6 版更改: 接受一个 类路径对象

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.

在 3.6 版更改: 接受一个 类路径对象

os.path.getsize(path)

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

在 3.6 版更改: 接受一个 类路径对象

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.

在 3.6 版更改: 接受一个 类路径对象

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.

在 3.6 版更改: 接受一个 类路径对象

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.

在 3.6 版更改: 接受一个 类路径对象

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.

在 3.6 版更改: 接受一个 类路径对象

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. It is not able to reliably detect bind mounts on the same filesystem. 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.

3.4 新版功能: 支持在Windows上检测非根安装点。

在 3.6 版更改: 接受一个 类路径对象

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.

在 3.6 版更改: 接受一个 类路径对象 用于 pathpaths

os.path.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.

在 3.6 版更改: 接受一个 类路径对象

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().

在 3.6 版更改: 接受一个 类路径对象

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).

注解

When symbolic link cycles occur, the returned path will be one member of the cycle, but no guarantee is made about which member that will be.

在 3.6 版更改: 接受一个 类路径对象

在 3.8 版更改: Symbolic links and junctions are now resolved on Windows.

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 默认为 os.curdir

可用性: Unix, Windows。

在 3.6 版更改: 接受一个 类路径对象

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.

可用性: Unix, Windows。

在 3.2 版更改: 添加了Windows 支持

在 3.4 版更改: Windows现在使用与其他所有平台相同的实现。

在 3.6 版更改: 接受一个 类路径对象

os.path.sameopenfile(fp1, fp2)

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

可用性: Unix, Windows。

在 3.2 版更改: 添加了Windows 支持

在 3.6 版更改: 接受一个 类路径对象

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().

可用性: Unix, Windows。

在 3.4 版更改: 添加了Windows 支持

在 3.6 版更改: 接受一个 类路径对象

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().

在 3.6 版更改: 接受一个 类路径对象

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")

在 3.6 版更改: 接受一个 类路径对象

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', '').

在 3.6 版更改: 接受一个 类路径对象

os.path.supports_unicode_filenames

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