Regex to return only first result from multiple matches

Question

Using c# vs2008 Regex

I am trying to get a number from a very long string loaded from text from a file.

In this source string there are multiple instances of the data i want to get out.
Eg. "Tax Invoice No INV1870507" may be repeated 10 times in the source String, with any unknown number of characters between each match. I want to get the number "1870507" out. The number is different for every different file I load and I need to find what the number is.

Using this pattern : (?<=Tax Invoice No[\s\r\n]+INV)(?'InvNo'[^\s\r\n]+)? I can correctly get a match on every occurance and can read the number.

But I get like 10 matches and 10 groups.

I want the Regex to short circuit at the first match and return only 1 match becasue then I have the info I need and there is no need to keep matching.

Can anyone please advise?

see http://stackoverflow.com/questions/2631183/c-sharp-regex-how-to-specify-to-only-match-first-occurrence — Hemant Metalia, Jan 04 '12 at 08:05

score 3 · Accepted Answer · answered Jan 04 '12 at 08:05

You want to use this for C#, so you can just use:

Regex regex = new Regex("(?<=Tax Invoice No[\s\r\n]+INV)(?'InvNo'[^\s\r\n]+)?");
regex.Match(myString);

Match: Searches the input string for the first occurrence of a regular expression...

That should actually do what you want.

Regex to return only first result from multiple matches

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