使用正则表达式在多行之间抓取文本

Question

I am trying to grab the word Juwelier that is before the tag from this HTML page code.

I am not very good with RegEx, and especially not with using it on multiple lines. Thing that will NOT be dynamic :

• <p>Rubriek:
• class="category"
• and ofcourse the html tags like <p> , </p> , <a> , </a>

This is the HTML page code

    <p>Rubriek: 

      <a href="http://www.detelefoongids.nl/juwelier/4-1/?oWhat=Juwelier"
         title="Juwelier"
         class="category">
           Juwelier
      </a>
   </p>

Answer 1

The Regex below is one among many that you could use.
It uses zero-width positive look-behind (?<=) and look-ahead (?=) assertions to locate the target string.

Dim str As String = _
"<p>Rubriek:" & vbCrLf &
"  <a href=""http://www.detelefoongids.nl/juwelier/4-1/?oWhat=Juwelier""" & vbCrLf &
"     title = ""Juwelier""" & vbCrLf &
"     class=""category"">" & vbCrLf &
"       Juwelier" & vbCrLf &
"  </a>" & vbCrLf &
"</p>"

Dim match As Match = Regex.Match(str, _
    "(?<=<p>Rubriek:[^>]+?class=""category"">\W*)\w+(?=\W*</a>)")

If (match.Success) Then
    MsgBox(match.Value)
End If

Although not used above, an important thing to remember when trying to match over multiple lines is to use Single-line mode if you are going to use the wild-card metacharacter . , so that it matches every character including new-lines . This can be specified using RegexOptions.Singleline or by putting (?s) at the start of the Regex.

\\w+ is used to match one or more word characters, ie a-zA-Z0-9_
\\W* is used to match zero or more non-word characters.
[^>] is used to match characters that are not > .