ruby - 拆分由子字符串列表分隔的字符串

Question

我有这样的数据:

str = "CODEA text for first item CODEB text for next item CODEB2 some"\
"more text CODEC yet more text"

和一个列表:

arr = ["CODEA", "CODEB", "CODEB2", "CODEC", ... ]

我想把这个字符串分成一个散列。散列的键将是 CODEA、CODEB 等。散列的值将是后面的文本，直到下一个 CODE。输出应如下所示:

"CODEA" => "text for first item",
"CODEB" => "text for next item",
"CODEB2" => "some more text",
"CODEC" => "yet more text"

Answer 1

我们得到了一个字符串和一个数组。

str = "CODEA text for first item CODEB text for next item " + 
      "CODEB2 some more text CODEC yet more text"

arr= %w|CODEC CODEB2 CODEA CODEB|
  #=> ["CODEC", "CODEB2", "CODEA", "CODEB"]     

这是获得所需哈希值的一种方法。

 str.split.
     slice_before { |word| arr.include?(word) }.
     map { |word, *rest| [word, rest.join(' ')] }.
     to_h
  #=> {"CODEA" =>"text for first item",
  #    "CODEB" =>"text for next item",
  #    "CODEB2"=>"some more text",
  #    "CODEC" =>"yet more text"}

参见 Enumerable#slice_before .

步骤如下。

a = str.split
  #=> ["CODEA", "text", "for", "first", "item", "CODEB",
  #    "text", "for", "next", "item", "CODEB2", "some",
  #    "more", "text", "CODEC", "yet", "more", "text"] 
b = a.slice_before { |word| arr.include?(word) }
  #=> #<Enumerator:
  #     #<Enumerator::Generator:0x00005cbdec2b5eb0>:each> 

我们可以看到将由该枚举器生成并通过将其转换为数组传递给 each_with_object 的 (4) 个元素(数组)。

b.to_a
  #=> [["CODEA", "text", "for", "first", "item"],
  #    ["CODEB", "text", "for", "next", "item"],
  #    ["CODEB2", "some", "more", "text"],
  #    ["CODEC", "yet", "more", "text"]] 

继续，

c = b.map { |word, *rest| [word, rest.join(' ')] }
  #=> [["CODEA", ["text for first item"]],
  #    ["CODEB", ["text for next item"]],
  #    ["CODEB2", ["some more text"]],
  #    ["CODEC", ["yet more text"]]] 
c.to_h
  #=> {"CODEA"=>"text for first item",
  #    "CODEB"=>"text for next item",
  #    "CODEB2"=>"some more text",
  #    "CODEC"=>"yet more text"} 

以下也许是更好的方法。

 str.split.
     slice_before { |word| arr.include?(word) }.
     each_with_object({}) { |(word, *rest),h|
       h[word] = rest.join(' ') }

当我还是个 child 的时候，这可能是这样完成的。

last_word = ''
str.split.each_with_object({}) do |word,h|
  if arr.include?(word)
    h[word]=''
    last_word = word
  else
    h[last_word] << ' ' unless h[last_word].empty?
    h[last_word] << word
  end     
end

last_word 必须设置为 block 外的任何内容。