Module 2 learning python -46

sys modify environment variables

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Only temporary modification

SYS Import 
sys.path.append () 

Example:

import sys
sys.path.append('C:\Users\hualong\PycharmProjects\test\day21\test.py')

 

To permanently modify, you need to change the environment variables in the System Properties

 

 

Add the absolute path:

import sys,os

if __name__ == '__main__':
    BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
    sys.path.append(BASE_DIR)

 

 

OS module

 

- Get current working path

print(os.getcwd())  

 

- Change the current working path

the os.chdir ( ' test0 ' ) into test0 # folder, return to the previous os.chdir ( '..')

 

 ---other

os.path.exists (path)        # If the path exists returns True, otherwise return False 
os.path.isabs (path)         # If the path is an absolute path, returns True 
os.path.isfile (path)        # If the path is an existing file returns True 
os.path.isdir (path)         # If the path is an existing directory, returns True 
os.path.join (path1, path2, ....)               # multiple return paths after stitching 
os.path. getatime (path)         # returns the last access time of the file or directory pointed to by path 
os.path.getmtime (path)       # returns the path of the file or directory pointed to by the last modified time

 

os.makdirs ( ' main / MAIN1 ' )         # generate a multi-layer recursive directory 
os.removedirs ( ' main / MAIN1 ' )       # delete main1 (only delete empty folders, if the main is empty delete) 
os.mkdir ()     # generate single-level directory 
os.rmdir ()     # delete a single stage empty directory 
os.listdir ()    # list all files and subdirectories in the specified directory 
the os.stat ()       # description file specified information 
os.sep          # output specified operating system the path separator 
os.linesep       # outputs the current line terminator platform 
os.pathsep       # output file path character string for dividing 
the os.name          # output string is simply the name of the current platform
os.system ()      #   display commands such as: dir information 
os.path.split ()      # split into a directory path and file name tuple back 
os.path.dirname () 
os.path.basename ()

 

 

sys module

 

. 1 the sys.argv         # command line parameter list, the first element of the program itself path 
2 the sys.exit (n-)      # exits the program, exit (0) when the normal exit 
. 3 The sys.version      # obtain python interpreter version information 
. 4 SYS. maxint        # maximum value of Int 
5 sys.path          # return module search path 
6 sys.platform      # return the name of the operating system platform

 

 Progress sub-regulations:

import sys,time
for i in range(100):

    sys.stdout.write('#')
    time.sleep(1)
    sys.stdout.flush()