39th, Python built-in global variables

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VARs () view built-in global variables

Returning a built-in global variable in a dictionary

# !/usr/bin/env python # -*-Coding:utf8-*- Print (VARs ()) # Output # {' __builtins__ ': <module ' builtins ' (built-in);, ' __spec__ ': None, ' __package__ ': None, ' __doc__ ': none, ' __n ame__ ': ' __main__ ', ' __cached__ ': None, ' __file__ ': ' h:/py/index.py ', ' __loader__ ': <_frozen_importlib_external. Sourcefileloader object at 0x000000ac32c66a58>}

__doc__ : Get comments for a file

# !/usr/bin/env python # -*-Coding:utf8-*- """ here is the comment of the file """ Print (__doc__)  # __doc__    : Get comments for file # output #  Here is the comment for the file

__file__ "Focus" gets the path to the current file

# !/usr/bin/env python # -*-Coding:utf8-*- Print (__file__)  # __file__: Gets the path to the current file # Output # h:/py/index.py

Will often use __file__, usually with the OS module os.path.dirname (), Os.path.basename (), Os.path.join () module functions to use

#!/usr/bin/env python#-*-Coding:utf8-*-ImportOSA=__file__    #__file__ global variable gets the current file pathPrint(a) b= Os.path.dirname (a)#get file current directory: note: os.path.dirname () overlay once to find the followingPrint(b) B2= Os.path.dirname (b)#gets the parent directory of the current directory of the file, note: os.path.dirname () overlay once to find oncePrint(B2) C= Os.path.basename (a)#Get file namePrint(c)#Output#h:/py/lib/ska/mk.py#H:/py/lib/ska#H:/py/lib#mk.py

__PACKAGE__: Get the path of the import file, multi-level directory with point segmentation, note: Return none for the current file

#!/usr/bin/env python#-*-Coding:utf8-*-Print(__package__)#Note: None is returned for the current file fromLib.skaImportMk#Import the Mk module filePrint(Mk.__package__)#__package__: Get the path of the import file, multi-level directory with point segmentation, note: Return none for the current file#Output#None#Lib.ska#Lib.ska

__CACHED__: Gets the cache path of the import file

# !/usr/bin/env python # -*-Coding:utf8-*-  from  Import Mk  # Imports MK module file print(Mk.__cached__#__ CACHED__: Gets the cache path of the import file # output #  H:\py\lib\ska\__pycache__\ MK.CPYTHON-35.PYC

__name__ "Focus" gets the path of the import file plus the file name, the path is split with points, note: Gets the current file returned __main__

#!/usr/bin/env python#-*-Coding:utf8-*-Print(__name__)#Note: Get the current file back __main__ fromLib.skaImportMk#Import the Mk module filePrint(Mk.__name__)#gets the path of the import file plus the file name, with the path separated by points#Output#__main__#lib.ska.mk

The __NAME__ global variable is written in the portal file, only the return value when executing the portal file is __main__, if the import file is imported into another file, the __name__ return value of the portal file is not __main__. Instead, if the file's path joins the port file name, we can use the __name__ global variable to prevent others from hotlinking the portal file

# !/usr/bin/env python # -*-Coding:utf8-*- if __name__ " __main__ " # The __name__  global variable is written in the portal file, only the return value when executing the portal file is __main__  , if the import file is imported into another file, the __name__ return value of the portal file is not __main__. Instead, if the file's path joins the port file name, we can use the __NAME__ global variable to prevent others from hotlinking the import file    print(" execute "  # This is done only when the index file is executed, and index is imported to another file, it will not be executed in the Judgment

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39th, Python built-in global variables