What Is __all_

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∟What Is __all__ List

This section provides a quick introduction on __all__ list, which is a special module attribute defined in the module file to override which members can be implicitly imported by the 'from module import *' statement.

What Is __all__ List? A __all__ list is a special module attribute defined in the module file to override which members can be implicitly imported by the "from module import *" statement.

Here is what I did to test the __all__ list.

1. Copy module_test.py to module_test_2.py and the __all__ list:

#  module_test_2.py
#- Copyright 2011 (c) HerongYang.com. All Rights Reserved.
#
print("Hi there! - from 'module_test' module")

version = "1.00 - from 'version' attribute"

def help():
   print("How can I help you? - from 'help()' function")

class first:
   print("Welcome on board! - from 'first' class")
   count = 0
   def rise(self):
      first.count += 1
      print(f"count = {first.count} - from 'rise()' method")

__all__ = ['help', 'first']

2. Run "from module_test_2 import *".

herong$ python

>>> from module_test_2 import *
Hi there! - from 'module_test' module
Welcome on board! - from 'first' class

>>> help()
How can I help you? - from 'help()' function

>>> o = first()
>>> o.rise()
count = 1 - from 'rise()' method

>>> version
NameError: name 'version' is not defined