Ruby-EnumRuby 快速定義枚舉
Ruby-Enum 是一組 Ruby 定義枚舉的便捷方式，可用于快速定義枚舉。
用法
枚舉可以作為常量或類方法定義和訪問。
常量
定義枚舉，并作為常量引用
class OrderState include Ruby::Enum define :CREATED, 'created' define :PAID, 'paid' end
OrderState::CREATED # 'created' OrderState::PAID # 'paid' OrderState::UNKNOWN # raises Ruby::Enum::Errors::UninitializedConstantError OrderState.keys # [ :CREATED, :PAID ] OrderState.values # [ 'created', 'paid' ] OrderState.to_h # { :CREATED => 'created', :PAID => 'paid' }
類方法
定義枚舉，并作為類方法引用
class OrderState include Ruby::Enum define :created, 'created' define :paid, 'paid' end
OrderState.created # 'created' OrderState.paid # 'paid' OrderState.undefined # NoMethodError is raised OrderState.keys # [ :created, :paid ] OrderState.values # ['created', 'paid']
默認(rèn)值
指可選，不選的話默認(rèn)為 key。
class OrderState include Ruby::Enum define :UNSPECIFIED define :unspecified end
OrderState::UNSPECIFIED # :UNSPECIFIED OrderState.unspecified # :unspecified
枚舉
支持所有Enumerable方法
迭代
OrderState.each do |key, enum| # key and enum.key are :CREATED, :PAID # enum.value is 'created', 'paid' end
OrderState.each_key do |key| # :CREATED, :PAID end
OrderState.each_value do |value| # 'created', 'paid' end
映射
OrderState.map do |key, enum| # key and enum.key are :CREATED, :PAID # enum.value is 'created', 'paid' [enum.value, key] end # => [ ['created', :CREATED], ['paid', :PAID] ]
排序
OrderState.sort_by do |key, enum| # key and enum.key are :CREATED, :PAID # enum.value is 'created', 'paid' enum.value.length end # => [[:PAID, #<OrderState:0x0 @key=:PAID, @value="paid">], [:CREATED, #<OrderState:0x1 @key=:CREATED, @value="created">]]
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