What's wrong with my VB.NET RegEx pattern?

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I'm converting some old VB6 code to VB.NET and have it all up and running, except that one particular RegEx pattern isn't finding a match that it should be. Here's the code:

VB

' Check for last, first middle (Doe, John P.)
pattern = "[^ \f\n\r\t\v\,]+\,\s+\S+ "
If Regex.IsMatch(strName, pattern) Then
    subParseLastFirst(strName)
Else
    ' Check for first middle last (John P. Doe)
    pattern = "^\S+\s+\S+\s+\S+$"
    If Regex.IsMatch(strName, pattern) Then
        subParseFirstMiddleLast(strName)
    Else
        ' Check for first last (John Doe)
        pattern = "^\S+\s+\S+$"
        If Regex.IsMatch(strName, pattern) Then
            subParseFirstLast(strName)
        Else
            mblnHasError = True
            mstrErrorMessage = "Unable to parse."
        End If
    End If
End If

When I feed "Doe, John" into the code, it doesn't match on the first pattern, but it does match on the third, which treats the name as first, last. If I feed Doe, John P., the first test is a match. How should I code the pattern for Doe, John, and where should it appear in the nested if?

Posted 31-Jul-14 10:53am

PeteKipe

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3 solutions

Solution 1

Dunno, maybe the \, ? Nuke it.

How about you try this one ^((?'last'\S+)(?'comma',))?\s*(?'first'\S+)\s*(?'middle'\S*?)(?(comma)|\s*(?'last'\S+))$ instead and access the Named Groups.
It still won't accept names that contain spaces (e.g. von Beethoven, Billy Ray X.), but it works for the examples:

Doe, John P.
Doe, John
John P. Doe
John Doe

Posted 31-Jul-14 11:21am

PIEBALDconsult

Updated 31-Jul-14 12:07pm

v3

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Peter Leow · Accepted Answer · 2014-07-31T15:09:00

Try this:

' Check for last, first middle (Doe, John P.)
^[a-zA-Z]+,\s[a-zA-Z]+\s[a-zA-Z]+.$

' Check for first middle last (John P. Doe)
^[a-zA-Z]+\s[a-zA-Z]+.\s[a-zA-Z]+$

' Check for first last (John Doe)
^[a-zA-Z]+\s[a-zA-Z]+$

and add one more else if for last, first of "Doe, John"

^[a-zA-Z]+,\s[a-zA-Z]+$

PeteKipe · Accepted Answer · 2014-07-31T16:11:00

Solution 3

Deleted solution, changed to comment.

Posted 31-Jul-14 16:11pm