Several common modules of Python

First, Sys

Used to provide actions related to the Python interpreter:

SYS.ARGV           command line argument list, the first element is the program itself path Sys.exit (n)        exits the program, exit normally (0) sys.version        Gets the version information of the Python interpreter Sys.maxint         the largest int value Sys.path           returns the search path for the module, using the value of the PYTHONPATH environment variable when initializing Sys.platform       Returns the operating system platform name Sys.stdin          input related sys.stdout         output related sys.stderror       error related

Second, OS

Used to provide system-level operations:

OS.GETCWD () Gets the current working directory, that is, the directory path of the current Python script work os.chdir ("DirName") changes the current script working directory, equivalent to the shell Cdos.curdir Return to current directory: ('. ') Os.pardir Gets the parent directory string name of the current directory: (' ... ') Os.makedirs (' Dir1/dir2 ') can generate a multi-level recursive directory Os.removedirs (' dirname1 ') if the directory is empty, then deleted, and recursively to the previous level of the directory, if also empty, then delete, and so on Os.mkdir (' DirName ' Generate a single-level directory, equivalent to the shell mkdir dirnameos.rmdir (' dirname ') delete the single-level empty directory, if the directory is not empty can not be deleted, error; equivalent to RmDir dirnameos.listdir in the shell (' dirname ') lists all files and subdirectories under the specified directory, including hidden files, and prints os.remove () Delete a file Os.rename ("Oldname", "new") Rename File/directory OS                  . Stat (' Path/filename ') gets file/directory information OS.SEP operating system-specific path delimiter, win under "\ \", Linux for "/" Os.linesep The current platform uses the line terminator, win under "\t\n", Linux for "\ n" os.pathsep the string used to split the file path Os.name string indicates the current use of the platform. Win-> ' NT ';       Linux-> ' POSIX ' Os.system ("Bash command") runs a shell command that directly displays the Os.environ get system environment variable Os.path.abspath (PATH) Return path normalized absolute path Os.path.split (path) splits path into directory and file name two tuples return Os.pathThe. DirName (path) returns the directory of path. In fact, the first element of Os.path.split (path) os.path.basename returns the last file name of path. If path ends with a/or \, then a null value is returned. The second element of Os.path.split (path), os.path.exists (path), returns True if path exists, or Falseos.path.isabs if path is not present if path is An absolute path that returns Trueos.path.isfile (path) If path is an existing file that returns TRUE. Otherwise, return Falseos.path.isdir (path) True if path is a directory that exists.  Otherwise return Falseos.path.join (path1[, path2[, ...]) When multiple paths are combined and returned, the parameters before the first absolute path are ignored Os.path.getatime (path) returns the file or directory to which path points to the last access time Os.path.getmtime (path) returns the file or directory that the path points to The last modified time

Several common modules of Python