Describes the definition and use of classes in Python and the definition of python.

Describes the definition and use of classes in Python and the definition of python.

A class, as its name implies, is a type of thing or an instance used to describe a type of thing with common characteristics. In python, we declare class keywords as class. Classes also have functions and attributes. attributes are the features of such things, and functions are what they can do, namely, methods or functions. We still use examples to illustrate the problem.

Objectives:

1. Class Definition

2. parent class, subclass definition, and subclass call parent class

3. Combined use of Classes

4. built-in functions

1. Class Definition

The Code is as follows:

#!/usr/bin/env python#coding:utf8class 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) * daysif __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. parent class, subclass, and calling parent class

The Code is as follows:

#! /Usr/bin/env python #-*-coding: UTF-8-*-# parent class AddBook (object): def _ init _ (self, name, phone ): self. name = name self. phone = phone def get_phone (self): return self. phone # subclass, inheriting class EmplEmail (AddBook): def _ init _ (self, nm, ph, email): # AddBook. _ init _ (self, nm, ph) # Call the parent class method super (EmplEmail, self ). _ init _ (nm, ph) # Call parent class method 2 self. email = email def get_email (self): return self. email # Call if _ name _ = "_ main _": Detian = AddBook ('handetianc', '000000') Meng = AddBook ('shaomeng ', '20140901') print Detian. get_phone () print AddBook. get_phone (Meng) alice = EmplEmail ('Alice ', '000000', 'Alice @ xkops.com') print alice. get_email (), alice. get_phone ()

3. Combined use of Classes

The Code is as follows:

#! /Usr/bin/env python #-*-coding: UTF-8-*-''' 1. class combination 2. mobile phones, mailboxes, and QQ can be changed (defined together), and the name cannot be changed (defined separately ). 3. reference '''class Info (object) in another class: 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 "cell phone number changed" def get_email (self): return self. emailclass 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 ('handetia ', '000000', 'destan @ xkops.com ', '000000') print Detian.info. get_phone () Detian.info. update_phone (18210413002) print Detian.info. get_phone () print Detian.info. get_email ()

4. built-in functions (difference between function () Addition and not addition)

The Code is as follows:

#!/usr/bin/env python#coding:utf8class 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:utf8class 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 Falseif __name__ == '__main__':  num = Number(10)  print num + 20  print 30 + num  print num - 5  print 11 - num  print num > 20

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