b import 了 a, c import 了 b，c 中也会有定义
test.py
1 __all__ = [‘a‘, ‘b‘] 2 3 def a(): 4 print "a" 5 6 def b(): 7 print "b" 8 9 def c(): 10 print "c"
test_2.py
1 from test import * 2 3 def a_2(): 4 print "a_2", 5 a()
test_3.py
1 from test_2 import * 2 3 a() 4 a_2()
运行 test_3.py
# a
# a_2 a
__all__ 的用法
test.py
1 __all__ = [‘a‘, ‘b‘] 2 3 def a(): 4 print "a" 5 6 def b(): 7 print "b" 8 9 def c(): 10 print "c"
test_2.py
1 from test import *
2
3 a()
4 # c() cause error
原文：http://www.cnblogs.com/mess4u/p/3963761.html