c#中的单独嵌套括号

Question

我想在给定的字符串中从内到外取值。所以，如果我的字符串中有括号，首先我必须达到最深的括号。之后，我必须采用后面的括号如何组合前一个字符串。我必须沿着字符串进行这些过程。

示例输入：

C1 AND [C2 OR C3 OR [C4 OR [C5 AND C6] AND C7]] OR C8

输出：

C5 AND C6
C4 OR [C5 AND C6] AND C7
C2 OR C3 OR [C4 OR [C5 AND C6] AND C7]
C1 AND [C2 OR C3 OR [C4 OR [C5 AND C6] AND C7]] OR C8

Answer 1

这是一个简单的堆栈实现；正则表达式不适用于此类解析问题：

private static IEnumerable<String> Nested(string value) {
  if (string.IsNullOrEmpty(value))
    yield break; // or throw exception

  Stack<int> brackets = new Stack<int>();

  for (int i = 0; i < value.Length; ++i) {
    char ch = value[i];

    if (ch == '[')
      brackets.Push(i);
    else if (ch == ']') {
      //TODO: you may want to check if close ']' has corresponding open '['
      // i.e. stack has values: if (!brackets.Any()) throw ...
      int openBracket = brackets.Pop();

      yield return value.Substring(openBracket + 1, i - openBracket - 1);
    }
  }

  //TODO: you may want to check here if there're too many '['
  // i.e. stack still has values: if (brackets.Any()) throw ... 

  yield return value;
}

...

string source = "C1 AND [C2 OR C3 OR [C4 OR [C5 AND C6] AND C7]] OR C8";

var result = Nested(source);

打印：

// C5 AND C6
// C4 OR [C5 AND C6] AND C7
// C2 OR C3 OR [C4 OR [C5 AND C6] AND C7]
// C1 AND [C2 OR C3 OR [C4 OR [C5 AND C6] AND C7]] OR C8
Console.Write(String.Join(Environment.NewLine, result));