I hear a rumor this is the place for online flex discussion.

I am a relative newbie and I want to match NMEA 0183 strings coming from a GPS.

They look like this:
$GPGGA,123519,4807.038,N,01131.000,E,1,08, 0.9,545.4,M,46.9,M,,*47

except when they look like this:

$GPGGA,123519,4807.038,N,01131.000,E,,,,,,,,,*47

In other words, many fields can be blank, but they are always comma - delimited. When they exist they are nicely structured, e.g. {DIGIT}{4}"."{DIGIT}{3} matches a latitude string.

So how do I distinguish between a field with some specific data and a delimiter, and an empty string followed by the same delimiter?

Thanks.

Eric