Ruby:有没有像 Enumerable#drop 这样返回枚举器而不是数组的东西? [英] Ruby: Is there something like Enumerable#drop that returns an enumerator instead of an array?

问题描述

我有一些固定宽度的大文件，我需要删除标题行.

I have some big fixed-width files and I need to drop the header line.

跟踪迭代器似乎不太习惯.

Keeping track of an iterator doesn't seem very idiomatic.

# This is what I do now.
File.open(filename).each_line.with_index do |line, idx|
  if idx > 0
     ...
  end
end

# This is what I want to do but I don't need drop(1) to slurp
# the file into an array.
File.open(filename).drop(1).each_line do { |line| ... }

Ruby 的成语是什么?

What's the Ruby idiom for this?

推荐答案

如果你不止一次需要它，你可以为 Enumerator 编写一个扩展.

If you need it more than once, you could write an extension to Enumerator.

class Enumerator
  def enum_drop(n)
    with_index do |val, idx|
      next if n == idx
      yield val
    end
  end
end

File.open(testfile).each_line.enum_drop(1) do |line|
  print line
end

# prints lines #1, #3, #4, …

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