在一个函数中，def a(l: List[(Int, String)]): List[(Int, String)] = ???我想将一个字符串拆分成小写的单词。逗号等应该被忽略，所以我想我需要replaceAll("[^A-Za-z]+", " ").toLowerCase()某个地方？Int 值应与句子中的值保持一致。

示例它应该如何工作：

val example = List((11, "That is great!"), (12, "Wow, impossible!"))
print(a(example)) 

结果

List((11, "that"),(11, "is"),(11, "great"),(12, "wow"),(12, "impossible"))

回答

val example = List((11, "That is great!"), (12, "Wow, impossible!"))
example.flatMap { case (int, str) =>
  str
    .replaceAll("[^A-Za-z]+", " ")
    .toLowerCase()
    .split(' ')
    .map((int, _))
}

res0: List[(Int, String)] = List((11,that), (11,is), (11,great), (12,wow), (12,impossible))