Find match of string in Regex, put into variable, tricky string

Question

I'm very new in this Regex, there's still a lot I don't understand.

I see a lot of @, but I can't find it in MSDN. What's the @ for? eg: Regex regex = new Regex("@{lalala},", RegexOptions.Compiled);
This is what I'm having trouble with. I have this string.

{BaseClass.InheritClass,Tuple.Create("MachineState",string.Empty)},

What I want to do is get the name of the InheritClass and MachineState, put it into variables.

I tried this:

Regex regex = new Regex(@"\{BaseClass.(?<inheritClassStr>\d+),Tuple.Create\(""(?<machineStateStr>\d+)"",string.Empty\)\},", RegexOptions.Compiled);

I was hoping later in the code I could do something like this:

string inheritClassString = inheritClassStr;
string machineStateString = machineStateStr;

But it doesn't work, and I do not know how to debug this. I don't know what the Regex captures, so it's very hard for me to debug.

Your help would be greatly appreciated.

Rafal · Accepted Answer · 2013-06-19 06:04:02Z

1

What you are after is (as in regular expression):

\{BaseClass.(?<inheritClassStr>.*?),Tuple.Create\("(?<machineStateStr>.*?)",string.Empty\)\}

to clarify:

\d that you used will math only numbers but identifiers in C# tend to contain letters as well.

.* would math any character in greedy manner (so the more the better) so it is not a good choice here

.*? will math any character but in not greedy manner (so as small set as possible)

And there is no magic in C# so your declarations in regex wont get converted to variables but you need to access those like this:

var inheritClassString = regex.Groups["inheritClassStr"].Value;

And the @ on the beginning of string just indicates that c# compiler wont try to interpret special characters that can be put in otherwise not prefixed string such as \t\n\r tab, new line, carriage return.

answered Jun 19, 2013 at 6:04

Rafal

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2 Comments

Farid Over a year ago

I still getting unrecognized escape sequence... I changed my Regex to: Regex regex = new Regex("\{BaseClass.(?<inheritClassStr>.*?),Tuple.Create(\"(?<machineStateStr>.*?)\",string.Empty)\}", RegexOptions.Compiled); Still failing. I have 4 unrecognized escape sequence :( If I never put escape sequence before the quotation mark, the RegEx will fail at the quotation mark...

Rafal Over a year ago

That is exactly the error that @ is for. Prefix your regex with @ replace \" with "" and your good to go.

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