VB.Net Regex Help
I've got 3 or 4 patterns that I'm comparing user input against and I need to figure out if the user input matches one of the patters and to return the match if it does.
Since the input is multiline, I'm passing each individual line like so:
Dim strRawInput() As String = Split(txtInput.Text, vbCrLf)
Dim strInput As String
txtOutput.Text = ""
For Each strInput In strRawInput
strInput.Trim(vbCr, vbLf, Chr(32))
Validation(strInput)
Next
Then I have this to find matches:
Dim m As Match
For i = 0 To strValidator.Length - 1
Dim r As New Regex(strValidator(i))
m = r.Match(strInput)
If m.Success Then
txtOutp开发者_如何转开发ut.Text = txtOutput.Text & "Success: " & m.ToString & vbCrLf
Exit Sub
Else
End If
Next
txtOutput.Text = txtOutput.Text & "Not this time" & vbCrLf
How can I do this more efficiently? Also, I added the Exit Sub there to avoid showing the "Not this time" message even after a match is found (if the match is with one of the later patterns in the array), but I'd like to find a better way of doing that too.
Thanks in advance.
Rather than generating your Regexs in the loop, generate them one time at the startup of the application. So maybe something like:
Private Shared m_regexes As New List(Of Regex)
Shared Sub New()
For Each v As String In strValidator
m_regexes.Add(New Regex(v))
Next
End Sub
And then you can change your other code to:
For Each r As Regex In m_regexes
Dim m As Match = r.Match(strInput)
If m.Success Then
txtOutput.Text = txtOutput.Text & "Success: " & m.ToString & vbCrLf
Exit Sub
Else
End If
Next
Regarding the Exit Sub
, I think it's fine, You've discovered that it matches at least one pattern, so why continue to evaluate the rest. But if you don't like methods that can "return" in multiple places, you could just replace it with a Boolean
and a Exit For
as:
Dim found as Boolean = false
For Each ...
If IsMatch Then
found = True
Exit For
End If
Next
If Found Then
....
Else
.....
End If
Hmm if that's the case then wouldn't this be even better?
For i = 0 To strValidator.Length - 1
Dim r As New Regex(strValidator(i))
Dim m As Match = r.Match(strInput)
If m.Success Then
txtOutput.Text = txtOutput.Text & "Success: " & m.ToString & vbCrLf
Exit Sub
End If
Next
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