zoukankan      html  css  js  c++  java
  • 如何在一个类中定义一些常量,每个对象都可以方便访问这些常量而不用重新构造?

    如何在一个类中定义一些常量,每个对象都可以方便访问这些常量而不用重新构造?
    
    class Document():
        WELCOME_STR = 'Welcome! The context for this book is {}.'
    a=Document()
    print type(a)
    print dir(a)
    print a.WELCOME_STR
    
    C:Python27python.exe "C:/Users/TLCB/PycharmProjects/untitled2/python study/t12.py"
    <type 'instance'>
    ['WELCOME_STR', '__doc__', '__module__']
    Welcome! The context for this book is {}.
    
    
    一种很常规的做法,是用全大写来表示常量,因此我们可以在类中使用 self.WELCOME_STR ,
    
    
    或者在类外使用 Entity.WELCOME_STR ,来表达这个字符串。
    
    
    在类外:
    
    node2:/root/python/object#cat t100.py
    class Document():
        WELCOME_STR = 'Welcome! The context for this book is {}.'
    node2:/root/python/object#
    node2:/root/python/object#cat t1.py 
    from  t100 import *;
    print Document.WELCOME_STR
    node2:/root/python/object#
    node2:/root/python/object#python t1.py 
    Welcome! The context for this book is {}.
  • 相关阅读:
    @codeforces
    @atcoder
    @loj
    @atcoder
    @atcoder
    @loj
    @atcoder
    @atcoder
    @atcoder
    @uoj
  • 原文地址:https://www.cnblogs.com/hzcya1995/p/13348370.html
Copyright © 2011-2022 走看看