ruby - 可以在每个循环的哈希中访问索引吗？

Question

我可能遗漏了一些明显的东西，但是有没有办法在每个循环的哈希内访问迭代的索引/计数？

hash = {'three' => 'one', 'four' => 'two', 'one' => 'three'}
hash.each { |key, value| 
    # any way to know which iteration this is
    #   (without having to create a count variable)?
}

Answer 1

如果您想知道每次迭代的索引，您可以使用.each_with_index

hash.each_with_index { |(key,value),index| ... }

Answer 2

您可以遍历键，并手动获取值：

hash.keys.each_with_index do |key, index|
   value = hash[key]
   print "key: #{key}, value: #{value}, index: #{index}\n"
   # use key, value and index as desired
end

编辑：根据rampion的评论，我也刚刚了解到，如果您迭代，您可以将键和值作为一个元组获取hash：

hash.each_with_index do |(key, value), index|
   print "key: #{key}, value: #{value}, index: #{index}\n"
   # use key, value and index as desired
end