python standard library principles and usage of the detailed article

path in os

Viewing the source code will show that theThere are a few lines in

if 'posix' in _names:
    name = 'posix'
    linesep = '\n'
    from posix import *
    # Omit some code

elif 'nt' in _names:
    from nt import *
    try:
        from nt import _exit
        __all__.append('_exit')
    except ImportError:
        pass
    import ntpath as path
    #。。。

Since we are in windows (Windows NT), open thefile, you can see that eight member variables are defined at the beginning

curdir = '.'    # Current path identifier
pardir = '..'   #
extsep = '.'    # extension separator
sep = '\\'
pathsep = ';'   # path separator in environment variables
altsep = '/'    #
defpath = '.;C:\\bin'   # Where environment variables are stored
devnull = 'nul'

In addition, there is a program calledsupports_unicode_filenamesis a boolean member variable indicating whether the current system supports unicode filenames.

It can be understood thatpathThe following is a list of operating system-related features that are encapsulated in the defaultfrom import *。

Single-parameter functions whose input is a path string

	exports
`normpath()`	Change the path to`\\a\\b`formality
`normcase()`	Change the path to lowercase`\\a\\b`formality
`abspath()`	Returns an absolute path in the form`X:\\a\\b`
`realpath()`	Returns the absolute path and eliminates the links in it
`relpath()`	Returns the relative path and eliminates the links in it
`split()`	Split the input path into two parts for example`X:\\a\\b`will return as`X:\\a`cap (a poem)`b`
`splitext()`	Split file extension
`splidrive()`	Splitting out drives and other paths
`basename()`	The name of the lowest level directory or file, the`split()[1]`
`dirname()`	The lowest directory or directory where the file is located, the`split()[0]`
`exists()`	Determine whether the input path exists, if it does, return`True`or else`False`
`lexists()`	If the path is corrupted, it also returns`False`
`isabs()`	Determine if the input path is an absolute path
`isfile()`	Determine if the input path is a file
`isdir()`	Determine if the input path is a directory
`islink()`	Determine if the input path is a link
`ismount()`	Determine if the input path is a mount point (in windows it's the disk drive letter) for example`('C:\\')`The return value is True.
`expanduser()`	pass (a bill or inspection etc)`~`Expanding on paths
`expandvars()`	Expanding paths into variables recognized by the command line

Some examples

>>> from  import *
>>> p = abspath('.')
>>> p
'E:\\Documents\\00\\1022'
>>> exists(p)
True
>>> splitdrive(p)
('E:', '\\Documents\\00\\1022')
>>> isfile(p)
False

Single parameter functions related to file information

The input must be a file path, not a directory.

exports~.getsize()Get file size in bytes~.getctime()Get the file creation time, c is create~.getmtime()Get the last modification time of the file, m is modify~.getatime()Get the last access time of the file, a i.e. access

	exports
`~.getsize()`	Get file size in bytes
`~.getctime()`	Get the file creation time, c is create
`~.getmtime()`	Get the last modification time of the file, m is modify
`~.getatime()`	Get the last access time of the file, a i.e. access

Functions whose inputs are multiple arguments

, for splicing paths, a super sweet feature. Many newbies will be troubled for the new folder, many times they don't know whether to write theD:\testneverthelessD:\test\while inin which the two are essentially equivalent.

>>> ('test','\\test1','test2\\','test3')
'\\test1\\test2\\test3'

	Determine if they are the same
`~.samefile(p1, p2)`	Determine if a directory or file is the same
`~.sameopenfile(fp1, fp2)`	Whether two open files point to the same file

commonpath(list)，commonprefix(list): Returns the longest path common to all paths in the list, i.e., the distance to the common parent folder of all files and folders. The difference between the two is that the latter will add a\。

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