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原标题:Ruby: Using the "index" method with "OR"
  • 时间:2010-01-29 00:05:18
  •  标签:
  • ruby

采用指数方法,我试图发现,如果某一变量存在价值,如果该变量确实存在,那么就会尝试另一个变数;像以下第3行:

a = [ "a", "b", "c" ]
a.index("b")   #=> 1
a.index("z" or "y" or "x" or "b")   #=> 1

意思是,如果阵列中找不到“z”,那么就会尝试“y”;如果找不到,则尝试X;如果找不到X,则会尝试b。

我如何正确这样做?

最佳回答

TIMTOWTDI。 但我倾向于使用Array#inject。

%w(x y z b).inject(nil) { |i, e| i or a.index(e) } #=> 1

这样做还有另一种方式,更类似于你的假编码。

class String
  def | other
    ->(e) { self==e || other==e }
  end
end

class Proc
  def | other
    ->(e) { self.call(e) || other==e }
  end
end

a.index(&( x  |  y  |  z  |  b )) #=> 1
问题回答

取决于您的最终目标。 如果你只想看到<条码>a有<条码>z、<条码>y、<条码>x或<条码><<><><>><>>><>>>>>>>,你可以做到:

(a & %w{z y x b}).length > 0   # gives true if a contains z, y, x and/or b.

我们看到,如果存在一个<>>交叉点<>,其中含有一些与一套预期数量相同的要素,那么就能够检测到是否有任何要素。





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