Regex to find unqoted commas?

Question

I'm thinking we can look for an even number of quotes to the left, and to the right of the comma... but I'm not quite sure how to write it. Anyone know?

Actually..you'd just have to check either (left or right).

I want to split on this, so it has to match only the comma.

Example:

one, "two, three"

Should be split into two strings:

['one', ' "two, three"']

Answer 1

Regex alone is not very good for determining nested conditions. Brace matching, quote matching etc, it just isn't really up to task. You can use a regex in combination with a loop to parse things, but on the other hand, it may be simpler to simply parse it yourself.

Maybe you could provide a few example strings to clarify what you need to match so I can answer better.

*edit: Looking at your proposed solution does it work with \\" where the \ is escaped, but not the "?

I suspect you'll find deficiencies in your regex if you're working with real world strings or complicated escape sequences. Likely this will not be the common case, but again, it is important to understand a regex is probably not what you actually want to do here. Regex has no concept of nested state, even for simple quotations escape sequences are hard to deal with correctly.

Answer 2

Why not use the Split method of the string class?

String[] s = someString.Split(",");
// s[0] would contain the portion to the left of the comma
// s[1] would contain the portion to the right of the comma

Answer 3

Nevermind... think I got it:

Regex("(?<=[^\"]*(?:\"[^\"]*\"[^\"])),");

Answer 4

Are you parsing CSV? Regex is a pretty bad way to do it. Having read CSV definition (easily googlable) you can write an automaton to do it. Or... you can just steal one of many ready solutions out on web already.