本文介绍了使用Rails时在Ruby中处理常量的最佳方法是什么?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一些常量,它们代表模型中一个字段中的有效选项。在Ruby中处理这些常数的最佳方法是什么?
I have some constants that represent the valid options in one of my model's fields. What's the best way to handle these constants in Ruby?
推荐答案您可以为此目的使用数组或哈希(在您的环境中) .rb):
You can use an array or hash for this purpose (in your environment.rb):
OPTIONS = ['one', 'two', 'three'] OPTIONS = {:one => 1, :two => 2, :three => 3}或一个枚举类,它允许您枚举常量和键用于关联它们:
or alternatively an enumeration class, which allows you to enumerate over your constants as well as the keys used to associate them:
class Enumeration def Enumeration.add_item(key,value) @hash ||= {} @hash[key]=value end def Enumeration.const_missing(key) @hash[key] end def Enumeration.each @hash.each {|key,value| yield(key,value)} end def Enumeration.values @hash.values || [] end def Enumeration.keys @hash.keys || [] end def Enumeration.[](key) @hash[key] end end然后可以从中得出:
class Values < Enumeration self.add_item(:RED, '#f00') self.add_item(:GREEN, '#0f0') self.add_item(:BLUE, '#00f') end并像这样使用:
Values::RED => '#f00' Values::GREEN => '#0f0' Values::BLUE => '#00f' Values.keys => [:RED, :GREEN, :BLUE] Values.values => ['#f00', '#0f0', '#00f']更多推荐
使用Rails时在Ruby中处理常量的最佳方法是什么?
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