Explain the definition and use of Python classes

A class, as its name implies, is a class of things, or an instance, used to describe a class of things that have common characteristics. The key word that we declare in python is class, the class also has functions and properties, properties are the characteristics of this kind of thing, and functions are what it can do, which are methods or functions. Let's still use examples.

Goal:

1. Class definition

2. Superclass, subclass definition, and subclass call superclass

3. Combination of classes

4. Built-in functions

1. Class definition

The code is as follows:

#!/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. Parent class, subclass and call parent class

The code is as follows:

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

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

  def get_phone(self):
    return self.phone

#  Subclass, inheritance 
class EmplEmail(AddBook):
  def __init__(self, nm, ph, email):
    # AddBook.__init__(self, nm, ph) #  Call the superclass method 1
    super(EmplEmail, self).__init__(nm, ph) #  Call the superclass method 2
    self.email = email

  def get_email(self):
    return self.email

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

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

  alice = EmplEmail('alice', '18210418888', 'alice@xkops.com')
  print alice.get_email(), alice.get_phone()

3. Combination of classes

The code is as follows:

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

'''
1.class A combination of classes 
2. Mobile phone, email, QQ Is variable (defined in 1 The name is immutable (defined separately). 
3. On the other 1 class 
'''

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 " The phone number change has been changed "

  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', 'detian@xkops.com', '123456')
  print Detian.info.get_phone()
  Detian.info.update_phone(18210413002)
  print Detian.info.get_phone()
  print Detian.info.get_email()

4. Built-in functions (the difference between function () plus and minus)

The code is as follows:

#!/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