Question

I have this:

string input = @"(+order: top* OR +order: first* OR +order: second* OR +order: third* OR +order: ""fourth top"" OR +order: fifth*)";

I need to get a regex that extracts from the above as follows:

“top, first, second, third, fourth top, fifth”

I made this

    public static string GetOrders(string input)
    {
        string pattern = @"order(.*)OR";

        List<string> orders = new List<string>();
        foreach (Match m in Regex.Matches(input, pattern))
            orders.Add(m.Value);

        return string.Join(", ", orders.ToArray());
    }

My regex pattern is incomplete. I thought I can just extract everythin between “+order:” and “OR”, but it’s not working. It doesn’t seem to iterate the elements, I just get the whole input string.

What am I doing wrong?

Answer 1

.* is greedy, matching from the first order to the last OR.

@"order(.*?)OR" would work but only for the first four matches; the fifth one isn’t followed by OR.

So a better regex would be

@"order:\s*(.*?)\s*(?:OR|\))"

Even better (assuming that the rule is “either the parameter contains no spaces and ends with *, or it contains spaces and is enclosed in "s”):

@"(?<=order:\s*)(?:""[^""]*""|[^""*\s]*)"