带索引的 Ruby `each_with_object`

我想要做a.each_with_object with index，以比这更好的方式：

a = %w[a b c]
a.each.with_index.each_with_object({}) { |arr, hash|  
  v,i = arr
  puts "i is: #{i}, v is #{v}" 
}

i is: 0, v is a
i is: 1, v is b
i is: 2, v is c
=> {}

有没有办法做到这一点而不需要v,i = arr ?

在你的例子中.each.with_index是多余的。我找到了这个解决方案：

['a', 'b', 'c'].each_with_object({}).with_index do |(el, acc), index|
  acc[index] = el
end
# => {0=>"a", 1=>"b", 2=>"c"}