替代類使用，節省程式碼，清晰簡潔
使用Struct
SelectOption = Struct.new(:display, :value) do
def to_ary
[display, value]
end
end
option_struct = SelectOption.new("Canada (CAD)", :cad)
puts option_struct.display
# Canada (CAD)
puts option_struct.to_ary.inspect
# ["Canada (CAD)", :cad]
使用類
class SelectOption
attr_accessor :display, :value
def initialize(display, value)
@display = display
@value = value
end
def to_ary
[display, value]
end
end
option_struct = SelectOption.new("USA (USD)", :usd)
puts option_struct.display
# USA (USD)
puts option_struct.to_ary.inspect
# ["USA (USD)", :usd]
臨時的資料結構
例如一個使用兩個日期來過濾表單資料的例子，你可以在過濾的地方使用兩個值，也可以建立一個FilterRange Struct結構， 這個結構有一個from_date和to_date屬性， 你或許需要一個方法來統計兩個日期間的資料，你也可以穿件一個類，但是用struct更簡單，同時幫你清理程式碼
require 'ostruct'
require 'date'
SelectOption = Struct.new(:from_date, :to_date) do
def filter_data(date)
return true if date>=from_date..date<=to_date
end
end
option_struct = SelectOption.new(Time.now, Time.now+10)
p option_struct.filter_data(Time.now+4)
類內部資料
class Person
Address = Struct.new(:street_1, :street_2, :city, :province, :country, :postal_code)
attr_accessor :name, :address
def initialize(name, opts)
@name = name
@address = Address.new(opts[:street_1], opts[:street_2], opts[:city], opts[:province], opts[:country], opts[:postal_code])
end
end
leigh = Person.new("Leigh Halliday", {
street_1: "123 Road",
city: "Toronto",
province: "Ontario",
country: "Canada",
postal_code: "M5E 0A3"
})
puts leigh.address.inspect
# <struct Person::Address street_1="123 Road", street_2=nil, city="Toronto", province="Ontario", country="Canada", postal_code="M5E 0A3">
作為測試使用的Stub
KCup = Struct.new(:size, :brewing_time, :brewing_temp)
colombian = KCup.new(:small, 60, 85)
brewer = Brewer.new(colombian)
expect(brewer.brew).to eq(true)
Struct相比較penstruct，速度快， 但是openStruct可以動態新增屬性，
australia = OpenStruct.new(:country => "Australia", :population => 20_000_000)
australia.name='jack'
p australia