python中模块的__all__属性详解

# kk.py 
class A(): 
  def __init__(self,name,age): 
    self.name=name 
    self.age=age 
class B(): 
  def __init__(self,name,id): 
    self.name=name 
    self.id=id 
def func(): 
  print 'func() is called!' 
def func1(): 
  print 'func1() is called!' 

#test_kk.py 
from kk import * #由于kk.py中没有定义__all__属性，所以导入了kk.py中所有的公有属性、方法、类 
a=A('python','24') 
print a.name,a.age 
b=B('python',123456) 
print b.name,b.id 
func() 
func1() 

#kk.py 
__all__=('A','func') #在别的模块中，导入该模块时，只能导入__all__中的变量，方法和类 
class A(): 
  def __init__(self,name,age): 
    self.name=name 
    self.age=age 
class B(): 
  def __init__(self,name,id): 
    self.name=name 
    self.id=id 
def func(): 
  print 'func() is called!' 
def func1(): 
  print 'func1() is called!' 

#test_kk.py 
from kk import * #kk.py中定义了__all__属性，只能导入__all__中定义的属性，方法和类 
a=A('python','24') 
print a.name,a.age 
func() 
#func1() #NameError: name 'func1' is not defined 
#b=B('python',123456) #NameError: name 'B' is not defined 

#kk.py 
def func(): #模块中的public方法 
  print 'func() is called!' 
def _func(): #模块中的protected方法 
  print '_func() is called!' 
def __func():#模块中的private方法 
  print '__func() is called!' 

#test_kk.py 
from kk import * #这种方式只能导入公有的属性，方法或类【无法导入以单下划线开头（protected）或以双下划线开头(private)的属性，方法或类】  
func() 
#_func() #NameError: name '_func' is not defined 
#__func() #NameError: name '__func' is not defined 

__all__=('func','__func','_A') #放入__all__中所有属性均可导入，即使是以下划线开头 
class _A(): 
  def __init__(self,name): 
    self.name=name 
def func():  
  print 'func() is called!'  
def func1():  
  print 'func1() is called!'  
def _func():  
  print '_func() is called!'  
def __func():  
  print '__func() is called!'  

from kk import *   
func()  
#func1() #func1不在__all__中，无法导入 NameError: name 'func1' is not defined 
#_func() #_func不在__all__中，无法导入 NameError: name '_func' is not defined 
__func() #__func在__all__中，可以导入 
a=_A('python') #_A在__all__中，可以导入 
print a.name 

#kk.py 
def func(): 
  print 'func() is called!' 
def _func(): 
  print '_func() is called!' 
def __func(): 
  print '__func() is called!' 

#test_kk.py 
from kk import func,_func,__func #可以通过这种方式导入public,protected,private 
func() 
_func() #NameError: name '_func' is not defined 
__func() #NameError: name '__func' is not defined 

#kk.py 
def func(): 
  print 'func() is called!' 
def _func(): 
  print '_func() is called!' 
def __func(): 
  print '__func() is called!' 

#test_kk.py 
import kk #也可以通过这种方式导入public,protected,private 
kk.func() 
kk._func() #NameError: name '_func' is not defined 
kk.__func() #NameError: name '__func' is not defined 

#kk.py 
import sys 
__all__ = ["func"] # 排除了 'sys' 
def func(): 
  print 'func() is called!' 

#test_kk.py 
from kk import * 
#print sys.path #NameError: name 'sys' is not defined 
func() 

__all__ = [
  "foo",
  "bar",
  "egg",
]