python模块和类在import上的区别

1、类属于模块的一部分。当我们要建立一个类时，通常我们新建一个py文件，例如新建立cn.py,这个cn便成为我们的模块。

2、然后在cn里面建立自己的类：

'''Created on 2011-11-1

@author: dudong0726
'''

class Person:
    '''
    classdocs
    '''
    Count = 0

    def __init__(self,name,age):
        '''
        Constructor
        @param: name the name of this person
        @param: age the age of this person  
        '''
        self.name = name
        self.age = age
        Person.Count += 1
        
    def detail(self):
        '''
         the detail infomation of this person
        '''
        print('name is ',self.name)
        print('age is ',self.age)
        print('there are '+str(Person.Count)+" person in the class") 
        

3、我们需要在另一个模块中使用这个类，有两种导入方式

     1）from cn import * 也就是从cn模块中把所有的东西都导入进来

 

'''Created on 2011-11-1

@author: dudong0726
'''
from cn import *

if __name__ == '__main__':
    p = Person('marry',21)
    p.detail()
    
    q = Person('kevin',24)
    q.detail()

  2）import cn 告诉python我们将要使用这个模块的东西，当我们使用时要在前面加上cn.来指明来自cn这个模块

 

'''
Created on 2011-11-1

@author: dudong0726
'''
import cn

if __name__ == '__main__':
    p = cn.Person('marry',21)
    p.detail()
    q = cn.Person('kevin',24)
    q.detail()

 

4、我们可以在cn模块中建立一个函数

 

'''
Created on 2011-11-1

@author: dudong0726
'''
def say(word):
    print(word)

class Person:
    '''
    classdocs
    '''
    Count = 0

    def __init__(self,name,age):
        '''
        Constructor
        @param: name the name of this person
        @param: age the age of this person  
        '''
        self.name = name
        self.age = age
        Person.Count += 1
        
    def detail(self):
        '''
         the detail infomation of this person
        '''
        print('name is ',self.name)
        print('age is ',self.age)
        print('there are '+str(Person.Count)+" person in the class") 
        

   

5、在另外的模块中调用这个函数

  你可以这样调用：

 

'''
Created on 2011-11-1

@author: dudong0726
'''
from cn import *

if __name__ == '__main__':
    p = Person('marry',21)
    p.detail()
    q = Person('kevin',24)
    q.detail()
    
    say("hello world")

 

 

    当然也可以这样：

'''
Created on 2011-11-1

@author: dudong0726
'''
import cn

if __name__ == '__main__':
    p = cn.Person('marry',21)
    p.detail()
    q = cn.Person('kevin',24)
    q.detail()
    
    cn.say("hello world")