ruby - 正则表达式 : if three letters are included

Question

我有几个词:hello, poison, world, search, echo ...我有一些字母 e, h, o现在我需要找到包含这些字母的所有单词。像 search, echo for e, h, o

我可以这样搜索:

words = %w[hello poison world search echo]
matched = words.select do |w|
  %w[e,h,o].all?{ |l| w =~ /#{l}/ }
end

问题是如果字母是 o, o, o 或 l, b, l 这个搜索将返回 true 像 open 或 boil，但我需要搜索包含三个 o 或两个 l 和一个 b

更新:

leters = "abc"
words.select{ |w| w.count(letters) >= 3 }

更新 2

错误的解决方案，示例:

"lllllll".count("lua") #=> 5

Answer 1

您确定要正则表达式吗？字符串支持计算其中的值，您可以使用该功能。像这样:

words = ["pool", "tool", "troll", "lot"]
letters = "olo"

#find how many of each letter we need
counts = {}
letters.each { |v| counts[v] = letters.count(v) }

#See if a given work matches all the counts
# accumulated above
res = words.select do |w|
  counts.keys.inject(true) do |match, letter| 
      match && (w.count(letter) == counts[letter])
  end
end