ruby - 如何从 Ruby 中的循环创建类的实例？

Question

我试图从一个循环中初始化一个类的实例，但我不确定如何命名该对象，以便它在每次迭代时都有一个新名称，所以我没有五个对象/实例都被调用“我的动物”？

my_array = ["Fluffy", "Lala", "Jo", "Cersei", "Berlin"]
my_array.each do |e|
    my_animal = Animal.new(e)
end


class Animal
attr_accessor :name
    def initialize (name)
        @name = name
    end


end

Answer 1

你可以这样做:

my_array = ["Fluffy", "Lala", "Jo", "Cersei", "Berlin", "Jo"]
arr = my_array.each_with_index.with_object([]) do |(e,i),a|
    a << Animal.send(:new, "#{e}#{i}")        
end
  #=> [#<Animal:0x007fe3e4087b20 @name="Fluffy0">,
  #    #<Animal:0x007fe3e4087a80 @name="Lala1">,
  #    #<Animal:0x007fe3e40879e0 @name="Jo2">,
  #    #<Animal:0x007fe3e4087940 @name="Cersei3">,
  #    #<Animal:0x007fe3e4087878 @name="Berlin4">,
  #    #<Animal:0x007fe3e31d5618 @name="Jo5">] 

arr.map(&:name)
  #=> ["Fluffy0", "Lala1", "Jo2", "Cersei3", "Berlin4", "Jo5"] 

或者，以下方式传达附加信息:

my_array = ["Fluffy", "Lala", "Jo", "Cersei", "Lala", "Jo", "Berlin", "Jo"]
arr = my_array.each_with_object([]) do |s,a|
  instance = a.reverse.find { |i| i.name =~ /^#{s}/ }
  if instance
    old_name = instance.name
     prefix, nbr = old_name.split(/(\d+)/)
    new_name = "#{prefix}#{((nbr.to_i)+1).to_s}"
  else 
    new_name = "#{s}0"
  end        
  a << Animal.send(:new, new_name)        
end
  #=> [#<Animal:0x007fe3e402e458 @name="Fluffy0">,
  #    #<Animal:0x007fe3e402e1b0 @name="Lala0">,
  #    #<Animal:0x007fe3e402dc38 @name="Jo0">,
  #    #<Animal:0x007fe3e402d120 @name="Cersei0">,
  #    #<Animal:0x007fe3e402c540 @name="Lala1">,
  #    #<Animal:0x007fe3e4097d68 @name="Jo1">,
  #    #<Animal:0x007fe3e4096d00 @name="Berlin0">,
  #    #<Animal:0x007fe3e4096698 @name="Jo2">] 
arr.map(&:name)
  #=> ["Fluffy0", "Lala0", "Jo0", "Cersei0", "Lala1", "Jo1", "Berlin0", "Jo2"]