如何访问每个闭包中的父集合？ [英] How to access the parent collection in a each closure?

问题描述

我正在寻找替换 * parent * 的东西。

I'm looking from something that to replace the *parent*.

%w[apple apples].each do |w|
   next if *parent*.includes? w + "s"
   puts w
end

# output: apples

推荐答案

每个是一个约定，没有一个父集合特别是传递给每一个。只是命名，例如

each is a convention, there is no concept of a "parent collection" for blocks in general or ones passed to each in particular. Just name it, eg

(parent = %w[apple apples]).each do |w|
  next if parent.includes? w + "s"
  puts w
end

方法传递父级，

例如

module Each2
 def each2
   each { |elem| yield(self, elem) }
 end
end

include Each2

%w[apple apples].each2 do |parent, w|
  next if parent.includes? w + "s"
  puts w
end

。

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