如何在 Ruby 中做到这一点？

Question

我在 ruby​​ 中有一个数组（列表？）：

allRows = ["start","one","two","start","three","four","start","five","six","seven","eight","start","nine","ten"]

我需要对此运行一个循环以获取一个列表，该列表将元素从“开始”直到遇到另一个“开始”，如下所示：

listOfRows = [["start","one","two"],["start","three","four"],["start","five","six","seven","eight"],["start","nine","ten"]]

Answer 1

基于 Array#split：

def group(arr, bookend)
  arr.inject([[]]) do |results, element|
    if (bookend == element)
      results << []
    end
    results.last << element

    results
  end.select { |subarray| subarray.first == bookend } # if the first element wasn't "start", skip everything until the first occurence
end

allRows = ["start","one","two","start","three","four","start","five","six","seven","eight","start","nine","ten"]
listOfRows = group(allRows, "start")
# [["start","one","two"],["start","three","four"],["start","five","six","seven","eight"],["start","nine","ten"]]

Answer 2

如果您可以使用 ActiveSupport（例如，在 Rails 内部）：

def groups(arr, delim)
  dels = arr.select {|e| == delim }
  objs = arr.split(delim)

  dels.zip(objs).map {|e,objs| [e] + objs }
end