[RESOLVED] RegEx questions!

:wave:Hi all,

I am a RegEx virgin and have no idea where to start. I have three questions which i would be more than gratefull if you could help me.

1. Where is the best place to start learning RegEx?
2. If i have an array list full of text, how can i search for a string which is in the list?

For example, if i enter the search string "bob test" in this text:
Hi there, this is bob giving a testing

it will return a true. However, if there is only one match, it will also return a true.

3. thirdly, how can i search and pick out the link which is surrounded with the following tags? <link>http://etc etc te</link>

CHeers,

Ken:confused:

RegExLib.com is the best place to start and for implementing with .net you could visit MSDN

I can answer 1 of your questions

1/ Try this

1. I use this free tool to learn/test regex patterns
http://www.ultrapico.com/Expresso.htm

2. Use a List(Of String) is a better choice than the old arraylist class. You can then call one of its find methods (Find, FindAll, FindIndex, FindLast....). MSDN even has an example on this.

3. Using regex.

Ok,

I've found that I can use the following regex to pick up the link, but how do i capture the text?

(<link>) will capture the first one, but how do i know when it is ending?

<[^<]+?> will capture all tags between which has < > enclosing it.

Could you please help me? I dont know how to capture the link enclosed between <link></link>

cheers

Try this pattern

Code:

---

Dim pattern as string = "(?<=\<link\>).+(?=\</link\>)"

---

' Regex match
Dim options As RegexOptions = RegexOptions.None
Dim regex As System.Text.RegularExpressions.Regex = New System.Text.RegularExpressions.Regex("<link\b[^>]*>(.*?)</link>")
Dim input As String = Me.TextBox1.Text

' Get matches
Dim matches As MatchCollection = regex.Matches(input)
Dim i As Integer
For i = 0 To matches.Count - 1
' TODO: Do something with result
System.Windows.Forms.MessageBox.Show(matches(i).Groups(1).Value, "Match")
Next i

vb Code:

' Regex match
        Dim options As RegexOptions = RegexOptions.None
        Dim regex As System.Text.RegularExpressions.Regex = New System.Text.RegularExpressions.Regex("<link\b[^>]*>(.*?)</link>")
        Dim input As String = Me.TextBox1.Text
 
        ' Get matches
        Dim matches As MatchCollection = regex.Matches(input)
        Dim i As Integer
        For i = 0 To matches.Count - 1
            ' TODO: Do something with result
            System.Windows.Forms.MessageBox.Show(matches(i).Groups(1).Value, "Match")
        Next i