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Vexing regex in VB, Pt. 2
I need to find table names that are located between two markers, "Begin InputTables" and "Begin OutputColumns". The table names are in turn located between double quotes. In the following example, I am looking for "AGCOUNTY", "ELIGIBILITY" and "X":
Begin InputTables
Name ="AGCOUNTY"
Name ="ELIGIBILITY"
Name ="X"
End
Begin OutputColumns
Since I'm looping through the text, I don't need or want to find these strings use a regex MatchCollection.
My question: why doesn't the following regex...
This regex...
Put another way, what regex can I use to place an unknown number of carriage returns in a lookahead in .Net?
Begin InputTables
Name ="AGCOUNTY"
Name ="ELIGIBILITY"
Name ="X"
End
Begin OutputColumns
My question: why doesn't the following regex...
(?<=^Begin InputTables\r*.*)X
... find the X in singleline mode?This regex...
(?<=^Begin InputTables\r\n.*)AGCOUNTY
... will find AGCOUNTY in multiline mode, and this regex...
(?<=^Begin InputTables\r\n.*\r\n.*)EL
... will find ELIGIBILITY in multiline mode.Put another way, what regex can I use to place an unknown number of carriage returns in a lookahead in .Net?
Are you wanting to find those 3 tables by their exact names, or would you prefer to grab the values matching something like:
Name ="[^"]*"
Multiline mode will make ^ match the beginning of any line, rather than just the beginning of the input string.
\s matches a space character, which can be a space, tab, newline or line feed. That might be what you're looking for?
.
This pattern might do the trick? It will capture the table names; you just need to extract them from the resulting array
(?s)(?<=^Begin InputTables(?:(?!Begin OutputColumns).)*)Name ="([^"]*)"
The (?:(?!Begin OutputColumns).)* part of the pattern says don't go past "Begin OutputColumns" trying to find a match.
ASKER
TerryAtOpus: eventually I'll need to match anything between double quotes that are in turn between "Begin InputTables" and "Begin OutputColumns", but for now I want to search for the tables by their exact names.
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ASKER
Should, but doesn't. It only finds the first match. On subsequent iterations, it misses "ELIGIBILITY" and "X".
Here's the code:
Here's the code:
Dim options As RegexOptions = RegexOptions.IgnoreCase Or RegexOptions.Multiline
Dim pattern As String = "(?ms)(?<=^Begin InputTables(?:(?!Begin OutputColumns).)*)Name =""" & findText & """"
Dim m As Match = Regex.Match(inputLines, pattern, options)ASKER
By the way, what's the "(?ms)"?
ASKER
TerryAtOpus: I got it. You were right. I am unworthy.
ASKER
How do people get so smart?
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but it won't work if the word Begin is not at the very start of the input text, which is the only thing that ^ matches.