使用一种方法生成另一个方法的多个实例 class

Question

我试图让一个方法启动另一个 class 的多个实例。

class Players
  def initialize(players)
    @players = players
  end
  def generate_boards
    @players.each do |player|
      board = BingoBoardGenerator.new
      player = BingoBoard.new(player, board.generate)
      p player
    end
  end
end

players = ["Nick","Jiyoon","Mae","Lawson","Matthew"]
plays = Players.new(players)
plays.generate_boards

p player 显示 BingoBoard 的五个实例已正确创建，但我不确定如何访问它们（或它们在哪里）。关于如何调用这些实例的任何帮助？通常我会这样做：

nick = BingoBoard.new("Nick", board.generate) 
nick.board

但是当我一起实例化它们时，我不知道如何set/access它们的实例名称。

Answer 1

如 user2864740 所示，您可以使用 :map 而不是 :each 来 return 一个 BingoBoard 实例数组。如果你想存储这些实例以供以后使用，你可以使用如下所示的记忆。第一次调用 :bingo_board_instances 时，将生成板并设置实例变量 @bingo_board_instances，以便以后调用 :bingo_board_instances 不会导致生成新板。

class Players
  def initialize(players)
    @players = players
  end

  def generate_boards
    @players.map do |player|
      board = BingoBoardGenerator.new
      BingoBoard.new(player, board.generate)
    end
  end

  def bingo_board_instances
    @bingo_board_instances ||= generate_boards
  end
end

虽然上面的代码工作得很好，但我认为更直观的解决方案是使用 Player class（而不是 Players），然后传入一个数组Player 实例初始化 BingoBoardGenerator。使用这种方法，您可以为每个玩家设置一个实例变量，并创建一个属于该玩家的唯一棋盘：

class BingoBoardGenerator

  def initialize(args)
    #dynamically set instance vars to handle n number of players
    args.fetch(:players).each_with_index do |player,index|
      instance_variable_set("@player_#{index+1}",player)
    end
  end

  def generate_boards
    instance_variables.map do |player|
      player = instance_variable_get(instance_var)
      #you will need to implement :generate_bingo_board on player...I would suggest using memoization so you can store the player's board for later retrieval
      player.generate_bingo_board
    end
  end
end

#I have no idea what your implementation looks like...
b = BingoBoardGenerator.new(players: [Player.new("Jen"),Player.new("Phil"),Player.new("Mary"),Player.new("Bert")])

b.generate_boards

这将使您能够更好地封装可能属于各个玩家的数据，包括向每个 Player 实例询问其 :board 的能力。

使用一种方法生成另一个方法的多个实例 class

Using a method to generate multiple instances of another class

ruby

multiple-instances

instances