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Detailed explanation of the implementation code for creating and using classes in Python

黄舟
黄舟Original
2017-07-26 15:55:281876browse

This article mainly introduces the creation and use of Python implementation classes. It analyzes the definition and use of Python classes based on simple calculator function examples. Friends in need can refer to the following

The examples in this article describe How to create and use Python implementation classes. Share it with everyone for your reference, the details are as follows:


#coding=utf8
#为了使除法总是会返回真实的商,不管操作数是整形还是浮点型。
from __future__ import pision
'''''
类是面向对象编程的核心,它扮演相关数据及逻辑的容器角色。
定义类语法:
class ClassName(base_class[es]):
     "optional documentation string"
     static_member_declarations
     method_declarations
----------------------------------------------------------------
使用class关键字定义类。
可以提供一个可选择的父类或者说基类。
如果没有合适的基类,就默认使用object作为基类。
class行之后是可选的文档字符串、静态成员定义、方法定义。
'''
class calculatorClass(object):
  '''''first class:calculatorClass'''
  #定义一个静态变量来保存当前版本号
  version=1.0
  #设置输入参数并给参数赋值
  def __init__(self,one=10,two=20):
    self.first=one
    self.second=two
  '''''加法'''
  def add(self):
    return self.first+self.second
  '''''减法,取正数'''
  def sub(self):
    if self.first > self.second :
      return (self.first-self.second)
    else:
      return (self.second-self.first)
  '''''乘法'''
  def mul(self):
    return self.first * self.second
  '''''除法'''
  def p(self):
    if self.second !=0:
      return self.first/self.second
    else:
      pass
  '''''取模'''
  def mod(self):
    if self.second !=0:
      return self.first%self.second
    else:
      pass
'''''
上面类创建一个静态变量version,用例保存版本信息。
__init__()是一个特殊方法当一个类实例被创建时,该方法会自动执行。
该方法可以被当做构建函数,但它并不创建实例。
它仅仅是对象创建后执行的第一个方法。
它的目的是执行一些该对象的必要的初始化工作。
'''
'''''创建一个计算机实例'''
cal=calculatorClass(5,2)
'''''通过创建的实例,调用类中的方法和属性'''
print "The current version:",cal.version
print "----------------------------------"
print "The two number add:",cal.add()
print "The two number sub:",cal.sub()
print "The two number mul:",cal.mul()
print "The two number p:",cal.p()
print "The two number mod:",cal.mod()

The running results are as follows:

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