I am trying to solve an problem where I am searching for a string within a string using regex. More accurately I am searching for the longest string within a string, allowing for missing or extra characters.

I have been around and around this problem and now I think that it is not possible with regex. So I thought I would ask the monks for enlightenment.

So here is the real world situation, equipment marked with both painted id letters and RFID tags are being verified. An image of the equipment is run through a OCR process and a string of characters is returned. Sometimes there are extra characters included before, inside or after the actual part number, caused by noisy image. From a separate process, the equipment's RFID tag is read.

This seems straight forward enough, but I need to allow for extra characters in the string being searched, and allow for missing characters from the string being searched for.

The simple example is find "ABC" in "DFGABCKBG".

The example where I fail to find a solution is, find "ABC" in "DFGAXBHCY" as "AXBHC", or "ABC" in "DFGAXBHY" as "AXB".

p.s.

I'm not yelling, the OCR text is all upper case.