Question

Medicare Eligibility EDI Example Responses is what I’m trying to match.

I have a string that looks like this:

LN:SMITHbbbbbbbbFN:SAMANTHAbbBD:19400515PD:1BN:123456PN:9876543210GP:ABCDEFGHIJKLMNOID:123456789012345bbbbbPC:123PH:8005551212CD:123456PB:123ED:20060101TD:2070101LC:NFI:12345678FE:20070101FT:20080101

I need a set of matches that look like this:

 Key | Value ------------------- LN  | SMITHbbbbbbbb FN  | SAMANTHAbb BD  | 19400515 ... etc 

I’ve been dealing with this all day, and I can’t seem to get an acceptable matching scenario. I’m about to program it procedurally with a for loop and finding indexes of colons if I can’t figure something out.

I’ve tried using negative lookahead and I’m not getting anywhere. This is C#, and I’m using this tester (.Net) while I’m testing, along with The Regex Coach (non .Net).

I’ve tried using this:

([\w]{2})\:(?![\w]{2}\:) 

But that only matches the keys and their colons, like ‘LN:’, ‘FN:’, etc.

If I use:

([\w]{2})\:(.+?)([\w]{2})\: 

It consumes the next matching two character key and colon as well, leading to me only matching every other key/value pair.

Is there a way for me to match these using RegEx in .Net correctly, or am I stuck with a more procedural solution? Keep in mind, I can’t assume that the keys will always be upper case letters. They could possibly include numbers, but they will always be two characters and then a colon.

Thanks in advance for any help I can get.

Answer 1

I think what you want is positive lookahead, not negative, so that you find the key-colon combo ahead of the current position, but you don’t consume it. This appears to work for your test example:

([\w]{2})\:(.+?)(?=[\w]{2}\:|$) 

Yielding:

 LN: SMITHbbbbbbbb FN: SAMANTHAbb BD: 19400515 PD: 1 BN: 123456 PN: 9876543210 ... 

Note: I added the colons in my test output, they aren’t captured by the regex.

EDIT: Thanks, Douglas, I’ve edited the regex to capture end-of-string so the last entry is captured, too.