Python——os.path模块

　　Python 2.7.8

　　该模块实现了一些关于路径名的函数。

os.path.abspath(path)

　　返回所给参数的绝对路径。

 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 (‘‘).

os.path.commonprefix(list) 

Return the longest path prefix (taken character-by-character) that is a prefix of all paths inlist. 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) 

返回 path所在的目录名。等价于 split() 函数返回的二元结果对的前一个元素。

 os.path.exists(path) 

若参数对应的路径path存在，返回真值，对于无效的符号链接返回假值。有的平台上如果不能在目标路径上执行 os.stat() 函数，即使参数路径path物理存在，该函数也可能返回假值。

 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().

New in version 2.4.

 os.path.expanduser(path) 

On Unix and Windows, return the argument with an initial component of ~ or ~user replaced by thatuser‘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 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). Raise os.error if the file does not exist or is inaccessible.

New in version 1.5.2.

Changed in version 2.3: 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 os.error if the file does not exist or is inaccessible.

New in version 1.5.2.

Changed in version 2.3: 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 os.error if the file does not exist or is inaccessible.

New in version 2.3.

 os.path.getsize(path) 

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

New in version 1.5.2.

 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() 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. 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. 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.

 os.path.join(path, *paths) 

连接一个或多个路径。

返回一个连接了path和*paths所有成员的路径，其间以一个目录分隔符(os.sep)分隔。如果*paths的最后一个成员是一个空字符串（""），那么连接后的结果将以目录分隔符结尾，否则连接后的结果不以目录分隔符结尾。

如果*paths的某个成员是绝对路径，那么这个路径前面的参数全部抛弃，连接从这个绝对路径后面开始并继续下去。

Windows下，*paths的某个成员是绝对路径不会改变盘符，除非某一个成员中包含盘符，那么这个路径前面的参数全部抛弃，路径连接会从新的盘符下开始。 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), 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.

 os.path.normpath(path) 

标准化参数中的路径名。去除多余的目录分隔符和中间目录。

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).

New in version 2.2.

 os.path.relpath(path[, start]) 

Return a relative filepath to path either from the current directory or from an optional startdirectory. 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.

Availability: Windows, Unix.

New in version 2.6.

 os.path.samefile(path1, path2) 

Return True if both pathname arguments refer to the same file or directory (as indicated by device number and i-node number). Raise an exception if a os.stat() call on either pathname fails.

Availability: Unix.

 os.path.sameopenfile(fp1, fp2) 

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

Availability: Unix.

 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().

Availability: Unix.

 os.path.split(path) 

Split the pathname path into a pair, (head, tail) where tail is the last pathname component andhead 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 drive specification 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.

New in version 1.3.

 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‘, ‘‘).

Changed in version 2.6: Earlier versions could produce an empty root when the only period was the first character.

os.path.splitunc(path) 

Split the pathname path into a pair (unc, rest) so that unc is the UNC mount point (such asr‘\\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.walk(path, visit, arg) 

Calls the function visit with arguments (arg, dirname, names) for each directory in the directory tree rooted at path (including path itself, if it is a directory). The argument dirnamespecifies the visited directory, the argument names lists the files in the directory (gotten from os.listdir(dirname)). The visit function may modify names to influence the set of directories visited below dirname, e.g. to avoid visiting certain parts of the tree. (The object referred to by names must be modified in place, using del or slice assignment.)

Note

Symbolic links to directories are not treated as subdirectories, and that walk()therefore will not visit them. To visit linked directories you must identify them withos.path.islink(file) and os.path.isdir(file), and invoke walk() as necessary.

Note

This function is deprecated and has been removed in Python 3 in favor of os.walk().

os.path.supports_unicode_filenames 

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

New in version 2.3.