通过忽略某些单词来查找的正则表达式

Question

我对正则表达式非常陌生。我想通过忽略“in”、“of”、“the”等常用词以及逗号、反斜杠等特殊字符来搜索字符串中的多个词。

我的代码

  Dim StringToSearchFrom As String = "Thus, one shifts one's focus in a variety of directions all at the same time"
  Dim PhraseToSearch As String = "focus variety directions"
  Dim found1 As Match = Regex.Match(StringToSearchFrom, Regex needed)
        If found1.Success Then
            MsgBox(found1.Index)
        Else

第一个正则表达式在尝试查找并返回PhraseToSearch 的第一个单词（焦点）的索引时应忽略完整的单词“in”、“a”和“of”。谢谢

Answer 1

您可以使用以下正则表达式，您必须动态构建。这是一个概念验证示例，它将在忽略“a”和“in”的字符串中捕获“焦点变化”：

Public Dim MyRegex As Regex = New Regex( _
      "focus(?:(?:\b(?:in|of|a|the)\b\s*|[\p{P}\p{S}\p{Z}]*)*)variety", _
    RegexOptions.IgnoreCase _
    Or RegexOptions.CultureInvariant _
    Or RegexOptions.Compiled _
    )

解释：

要使字符串的一部分成为可选的，我们仍然应该能够在模式中捕获它。如果您将查询字符串中的所有可选子字符串替换为(?:(?:\b(?:in|of|a|the)\b\s*|[\p{P}\p{S}\p{Z}]*)*)，您将能够匹配单词列表(?:in|of|a|the)（使用您的单词列表更新）、标点符号\p{P}、符号\p{S}、空格@ 中的任何单词987654326@.

  Dim StringToSearchFrom As String = "Thus, one shifts one's focus in a variety of directions all at the same time"
  Dim PhraseToSearch As String = "focus variety directions"
  Dim optional_pattern As String = "(?:(?:\b(?:in|of|a|the)\b\s*|[\p{P}\p{S}\p{Z}]*)*)" 
  Dim rgx_Optional As New Regex(optional_pattern)
  PhraseToSearch = rgx_Optional.Replace(PhraseToSearch, optional_pattern)
  Dim rgx_Search As New Regex(PhraseToSearch)
  ' And then apply our regex
  Dim found1 As Match = rgx_Search.Match(StringToSearchFrom)
    If found1.Success Then
        MsgBox(found1.Index)
    Else