Q:

I have a comma delimited string and I want to find one particular field in that using Regex in C#

This is my string:
"0949418001","12/12/2011","12/21/2011","0010043309","EFT  ","Net 10 Days From Ship Date","","","FOB Origin/Collect","","","0000835369","DUPRE TRANSPORTS INC","DUPR      ","0231653047","1/23/2012","Motor Fuel Dest","1049930","8784.00","8796.00","8784.00","UG6  ","N","0.196500","1726.06","25405.51","TAX ","REG","","PASADENA,TX,COP,RFYC (03FV)","   ","0000835369","835369","1726.06","01/23/2012","0.00","23679.45"

I want to get the date that is preceding the word "Motot Fuel Dest" using regex.  How can we get that?  

A:

Could use something like this...
/(?<=")[^"]+(?=","Motor Fuel Dest)/

Depending on your regex flavor the syntax may be different. 
Edit: .NET version of solution
resultString = Regex. Match(subjectString, "(? <=\")[^\"]+(?=\",\"Motor Fuel Dest)").Value;

It's not something special, just lookbehind/lookahead capture only what you need.