os. path: Detailed explanation of the principle and usage of python standard library

path in os

When you look at the source code, you will see that in the os.py There are several lines like this in

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

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 (WindowsNT), open ntpath.py File, you can see that eight member variables are defined at the beginning

curdir = '.'    # Current path identification 
pardir = '..'   #
extsep = '.'    # Extension separator 
sep = '\\'
pathsep = ';'   # Delimiter of path in environment variable 
altsep = '/'    #
defpath = '.;C:\\bin'   # Location of environment variables 
devnull = 'nul'

In addition, there is another named supports_unicode_filenames Indicates whether the current system supports the file name of unicode.

It can be understood that, path Encapsulated in 1 and operating system-related, and different operating system code under different functions, the following default from os.path import * .

One-parameter function entered as a path string

	输出
CODE_TAG_REPLACE_MARK_5	将路径修改为 CODE_TAG_REPLACE_MARK_6 形式
CODE_TAG_REPLACE_MARK_7	将路径修改为小写的 CODE_TAG_REPLACE_MARK_6 形式
CODE_TAG_REPLACE_MARK_9	返回绝对路径，其格式为 CODE_TAG_REPLACE_MARK_10
CODE_TAG_REPLACE_MARK_11	返回绝对路径，并消除其中的链接
CODE_TAG_REPLACE_MARK_12	返回相对路径，并消除其中的链接
CODE_TAG_REPLACE_MARK_13	将输入路径分割为两个部分 例如 CODE_TAG_REPLACE_MARK_10 会返回为 CODE_TAG_REPLACE_MARK_15 和 CODE_TAG_REPLACE_MARK_16
CODE_TAG_REPLACE_MARK_17	分割文件的扩展名
CODE_TAG_REPLACE_MARK_18	分割出驱动器和其他路径
CODE_TAG_REPLACE_MARK_19	最下层的目录或文件名称，即 CODE_TAG_REPLACE_MARK_20
CODE_TAG_REPLACE_MARK_21	最下层目录或文件所在目录，即 CODE_TAG_REPLACE_MARK_22
CODE_TAG_REPLACE_MARK_23	判断输入路径是否存在，存在则返回 CODE_TAG_REPLACE_MARK_24 ，否则 CODE_TAG_REPLACE_MARK_25
CODE_TAG_REPLACE_MARK_26	如果路径损坏，也返回 CODE_TAG_REPLACE_MARK_25
CODE_TAG_REPLACE_MARK_28	判断输入路径是否为绝对路径
CODE_TAG_REPLACE_MARK_29	判断输入路径是否为文件
CODE_TAG_REPLACE_MARK_30	判断输入路径是否为目录
CODE_TAG_REPLACE_MARK_31	判断输入路径是否为链接
CODE_TAG_REPLACE_MARK_32	判断输入路径是否为挂载点（在windows中就是盘符） 例如 CODE_TAG_REPLACE_MARK_33 ，返回为True
CODE_TAG_REPLACE_MARK_34	通过 CODE_TAG_REPLACE_MARK_35 对路径进行扩展
CODE_TAG_REPLACE_MARK_36	将路径扩展为命令行识别的变量

Partial examples

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

Single parameter function related to file information

The input must be a file path, not a directory

Output ~.getsize() Get the 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 is access

	输出
CODE_TAG_REPLACE_MARK_37	以字节为单位获取文件大小
CODE_TAG_REPLACE_MARK_38	获取文件创建时间，c即create
CODE_TAG_REPLACE_MARK_39	获取文件最后修改时间，m即modify
CODE_TAG_REPLACE_MARK_40	获取文件最后访问时间，a即access

Functions with multiple inputs

os.path.join For splicing paths, super sweet 1 function. Many novices will be troubled by creating new folders, and often they don't know if they are writing D:\test Or D:\test\ , and in os.path.join The two are basically equivalent.

>>> os.path.join('test','\\test1','test2\\','test3')
'\\test1\\test2\\test3'

	判断是否相同
CODE_TAG_REPLACE_MARK_49	判断目录或文件是否相同
CODE_TAG_REPLACE_MARK_50	两个打开的文件是否指向同1个文件

normpath()1 , normpath()2 Returns the longest path common to all path in list, that is, the common parent folder from all files and folders. The difference between the two is that the latter will add on the return path normpath()3 .