Ruby each_with_index 偏移量 [英] Ruby each_with_index offset

问题描述

我可以在 each_with_index 循环迭代器中定义索引的偏移量吗?我的直接尝试失败了:

Can I define the offset of the index in the each_with_index loop iterator? My straight forward attempt failed:

some_array.each_with_index{|item, index = 1| some_func(item, index) }

澄清:我不想要数组偏移量，我希望 each_with_index 中的索引不是从 0 开始，而是例如1.

Clarification: I don't want an array offset I want that the index within the each_with_index doesn't start from 0 but e.g. 1.

推荐答案

其实Enumerator#with_index 接收偏移量作为可选参数:

Actually, Enumerator#with_index receives offset as an optional parameter:

[:foo, :bar, :baz].to_enum.with_index(1).each do |elem, i|
  puts "#{i}: #{elem}"
end

输出:

1: foo
2: bar
3: baz

顺便说一句，我认为它只存在于 1.9.2 中.

BTW, I think it is there only in 1.9.2.

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