详解Python中类的定义与使用

类顾名思义，就是一类事物、或者叫做实例，它用来描述具有共同特征的一类事物。我们在python中声明类的关键词是class，类还有功能和属性，属性就是这类事物的特征，而功能就是它能做什么，也是就是方法或者函数。我们仍然用例子来说明问题。

目标：

1.类的定义

2.父类，子类定义，以及子类调用父类

3.类的组合使用

4.内置功能

1.类的定义

代码如下：

#!/usr/bin/env python
#coding:utf8


class Hotel(object):
  """docstring for Hotel"""
  def __init__(self, room, cf=1.0, br=15):
    self.room = room
    self.cf = cf
    self.br = br

  def cacl_all(self, days=1):
    return (self.room * self.cf + self.br) * days

if __name__ == '__main__':
  stdroom = Hotel(200)
  big_room = Hotel(230, 0.9)
  print stdroom.cacl_all()
  print stdroom.cacl_all(2)
  print big_room.cacl_all()
  print big_room.cacl_all(3)

2.父类、子类以及调用父类

代码如下：

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# 父类
class AddBook(object):
  def __init__(self, name, phone):
    self.name = name
    self.phone = phone

  def get_phone(self):
    return self.phone

# 子类，继承
class EmplEmail(AddBook):
  def __init__(self, nm, ph, email):
    # AddBook.__init__(self, nm, ph) # 调用父类方法一
    super(EmplEmail, self).__init__(nm, ph) # 调用父类方法二
    self.email = email

  def get_email(self):
    return self.email

# 调用
if __name__ == "__main__":
  Detian = AddBook('handetian', '18210413001')
  Meng = AddBook('shaomeng', '18210413002')

  print Detian.get_phone()
  print AddBook.get_phone(Meng)

  alice = EmplEmail('alice', '18210418888', '[email protected]')
  print alice.get_email(), alice.get_phone()

3.类的组合使用

代码如下：

#!/usr/bin/env python
# -*- coding: utf-8 -*-

'''
1.class类的组合使用
2.手机、邮箱、QQ等是可以变化的（定义在一起），姓名不可变（单独定义）。
3.在另一个类中引用
'''

class Info(object):
  def __init__(self, phone, email, qq):
    self.phone = phone
    self.email = email
    self.qq = qq

  def get_phone(self):
    return self.phone

  def update_phone(self, newphone):
    self.phone = newphone
    print "手机号更改已更改"

  def get_email(self):
    return self.email


class AddrBook(object):
  '''docstring for AddBook'''
  def __init__(self, name, phone, email, qq):
    self.name = name
    self.info = Info(phone, email, qq)


if __name__ == "__main__":
  Detian = AddrBook('handetian', '18210413001', '[email protected]', '123456')
  print Detian.info.get_phone()
  Detian.info.update_phone(18210413002)
  print Detian.info.get_phone()
  print Detian.info.get_email()

4.内置功能(函数（）加与不加的区别）

代码如下：

#!/usr/bin/env python
#coding:utf8

class Books(object):
  def __init__(self, title, author):
    self.title = title
    self.author = author

  def __str__(self):
    return self.title

  def __repr__(self):
    return self.title

  def __call__(self):
    print "%s is written by %s" %(self.title, self.author)


if __name__ == '__main__':
  pybook = Books('Core Python', 'Wesley')
  print pybook
  pybook()

#!/usr/bin/env python
#coding:utf8

class Number(object):
  """Custum object
  add/radd -> +; 
  sub/rsub -> -;
  mul/rmul -> *;
  div/rdiv -> /;
  """
  def __init__(self, number):
    self.number = number

  def __add__(self, other):
    return self.number + other    

  def __radd__(self, other):
    return self.number + other

  def __sub__(self, other):
    return self.number - other

  def __rsub__(self, other):
    return other - self.number


  def __gt__(self, other):
    if self.number > other:
      return True
    return False


if __name__ == '__main__':
  num = Number(10)
  print num + 20
  print 30 + num
  print num - 5
  print 11 - num
  print num > 20