ReBuildAll Blog
Thoughts (mostly) on .NET development

The other day I needed to process CSV data from a .NET program. The basic processing is quite simple, you can just call string.Split() to have the job done. But I was faced with a CSV file that contained items in quotes. And of course inside the quotes, a comma would be allowed, thus rendering string.Split() quite useless.

I asked around and found that people were using a library that can be obtained from CodeProject. You can find the actual project here. It provides quite robust CSV processing capabilities. Unfortunately, I was in a hurry, and did not want to play around with a library (I know: bad me). I needed a regular expression that could split my string.

As it turned out, there were some articles to be found around the internet, but none would offer a perfect solution. I finally stitched together a regex from various sources and Google cache entries.

Regex rex = new Regex(",(?=(?:[^\"]*\"[^\"]*\")*(?![^\"]*\"))");

This would work for my case. It might not be general enough, but if you have CSVs with quotes and need a fast solution, you can just take the above regex and then use it to split:

string[] result = rex.Split(csvLine);