紅寶石中的隨機對象，需要異常處理的幫助

Question

我正在嘗試編寫掃雷遊戲以獲得樂趣。到目前爲止，我正在研究一個董事會和我的對象，最終將會在董事會中得到充分利用。目前，當我爲測試目的製作5×5板並將其加載到我的地雷對象中時，它可以選取隨機的列行，但部分時間會出錯。下面是代碼，我跑什麼，錯誤我得到：

class Board 
    attr_accessor :size, :board 

    def initialize(size = gets.chomp.to_i) 
    @size = size 
    @board = (1..@size).map { |x| ["L"] * @size } 
    end 

    def print_board 
    @board.map { |row| puts row.join } 
    end 
end 

class Mine 
    attr_accessor :proxi, :row, :col 

    def initialize(proxi) 
    @proxi = proxi 
    @row = Random.rand(1..@proxi.board.length) 
    @col = Random.rand(1..@proxi.board[0].length) 
    check_position 
    end 

    def check_position 
    if @proxi.board[@row - 1][@col - 1] != "L" 
     initialize 
    else 
     map_position 
    end 
    end 

    def map_position 
    @proxi.board[@row - 1][@col - 1] = "*" 
    end 
end 

b = Board.new(5) 

=> #<Board:0x000000024cbb50 @size=5, @board=[["L", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"]]> 

m = Mine.new(b) 

=> #<Mine:0x000000024ae9d8 @proxi=#<Board:0x000000024cbb50 @size=5, @board=[["L", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"], ["L", "L", "*", "L", "L"], ["L", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"]]>, row3, col3 

m = Mine.new(b) 

=> #<Mine:0x00000002487888 @proxi=#<Board:0x000000024cbb50 @size=5, @board=[["L", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"], ["L", "L", "*", "L", "L"], ["*", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"]]>, row4, col1 

m = Mine.new(b) 

=> #<Mine:0x000000024758b8 @proxi=#<Board:0x000000024cbb50 @size=5, @board=[["L", "L", "L", "L", "L"], ["L", "L", "L", "L", "L"], ["L", "L", "*", "L", "L"], ["*", "L", "*", "L", "L"], ["L", "L", "L", "L", "L"]]>, row4, col3 

m = Mine.new(b) 

=> #<Mine:0x000000024211a0 @proxi=#<Board:0x000000024cbb50 @size=5, @board=[["L", "L", "L", "*", "L"], ["L", "L", "L", "L", "L"], ["L", "L", "*", "L", "L"], ["*", "L", "*", "L", "L"], ["L", "L", "L", "L", "L"]]>, row1, col4 

m = Mine.new(b) 

=> #<Mine:0x000000023b37e0 @proxi=#<Board:0x000000024cbb50 @size=5, @board=[["L", "L", "L", "*", "L"], ["L", "L", "L", "L", "L"], ["*", "L", "*", "L", "L"], ["*", "L", "*", "L", "L"], ["L", "L", "L", "L", "L"]]>, row3, col1 

m = Mine.new(b) 

=> #<Mine:0x0000000235ed08 @proxi=#<Board:0x000000024cbb50 @size=5, @board=[["L", "L", "L", "*", "L"], ["L", "L", "L", "*", "L"], ["*", "L", "*", "L", "L"], ["*", "L", "*", "L", "L"], ["L", "L", "L", "L", "L"]]>, row2, col4 

m = Mine.new(b) 

=> #<Mine:0x00000002310888 @proxi=#<Board:0x000000024cbb50 @size=5, @board=[["L", "L", "L", "*", "L"], ["L", "L", "L", "*", "L"], ["*", "L", "*", "L", "*"], ["*", "L", "*", "L", "L"], ["L", "L", "L", "L", "L"]]>, row3, col5 

m = Mine.new(b) 

ArgumentError: wrong number of arguments (0 for 1) 
    from (irb):16:in `initialize' 
    from (irb):25:in `check_position' 
    from (irb):20:in `initialize' 
    from (irb):43:in `new' 
    from (irb):43 
    from /home/ubuntu/.rvm/rubies/ruby-2.0.0-p353/bin/irb:12:in `<main>' 

所以最終，當我養活一個新的對象實例的修改實例董事會不採取。我不確定這是爲什麼，但希望有人能引導我走向正確的方向，這樣我就可以實現自動化。謝謝！

這裏是我去解決：

class Mine 
    attr_accessor :proxi, :row, :col 

    def initialize(proxi) 
    @proxi = proxi 
    @row = 0 
    @col = 0 
    @random = Random.new 
    check_position 
    end 

    def check_position 
    if @proxi.board[@row - 1][@col - 1] != "L" 
     @row = @random.rand(1..@proxi.board.length) 
     @col = @random.rand(1..@proxi.board[0].length) 
     check_position 
    else 
     map_position 
    end 
    end 

    def map_position 
    @proxi.board[@row - 1][@col - 1] = "*" 
    end 
end 

Answer 1

你check_position方法嘗試如果位置已經被帶到回打電話initialize，但未能通過所需proxi參數。

我認爲它不明智（如果可能）重新調用initialize方法，因爲這是您的類的構造函數。

我寧願將與找到開放位置相關的邏輯提取到一組輔助方法。像下面的內容將幫助你到達那裏：

private 

    def find_open_position 
    x = 0 
    y = 0 

    begin 
     x, y = random_position 
    while position_taken?(x, y) 

    [x, y] 
    end 

    def random_position 
    [Random.rand(1..@proxi.board.length), @col = Random.rand(1..@proxi.board[0].length)] 
    end 

    def position_taken?(x, y) 
    @proxi.board[x - 1][x - 1] != "L" 
    end 

然後你initialize僅需要包括

@row, @col = find_open_position