Converting regular expression from java to .Net

Question

I'm converting a project from java to C#. I have no idea what the equivalence of following regular expression would be in C#.

The regular expression : Customer rating (?<rating>\d.\d)/5.0
The java string : "Customer rating (?<rating>\\d.\\d)/5.0"

This is the java code:

private static final Pattern ratingPattern = Pattern.compile("Customer rating (?<rating>\\d.\\d)/5.0");
...
m = Retriever.ratingPattern.matcher(X);
if (m.matches()) {
...
}

and it works for ( X=Customer rating 1.0/5.0 ). But this is the C# code:

static Regex rx = new Regex(@"Customer rating (?<rating>\\d.\\d)/5.0");
...
MatchCollection matches = rx.Matches(X);
if (matches.Count > 0)
{
...
}

and it doesn't work for ( X=Customer rating 1.0/5.0 ).I mean (Matches.count) is always 0 for ( X=Customer rating 1.0/5.0 )

Please help me if you have any ideas.

Thank you

Avinash Raj · Accepted Answer · 2015-03-14 10:59:02Z

2

You don't need to escape the baclslash one more time if the regex was present within a verbatim string.

@"Customer rating (?<rating>\d\.\d)/5\.0"

And also escape all the dots present in your regex, since dot matches any character not only a literal dot.

Inside a verbatim string, \\d matches a literal backslash and a character d. So your regex searches for a backslash and a literal d. since there isn't any, your regex got failed.

edited Mar 14, 2015 at 10:59

answered Mar 14, 2015 at 10:51

Avinash Raj

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Avinash Raj Over a year ago

or use this "Customer rating (?<rating>\\d\\.\\d)/5\\.0" without @

Kavindu Dodanduwa · Accepted Answer · 2015-03-14 12:08:59Z

0

Solution is to use @ varbitm literal to define regex with escape sequences like back slash \

So code would be :

  Regex rx = new Regex(@"Customer rating (?<rating>\d\.\d)\/5\.0"); // <= Updated and cleaned regex

  MatchCollection matches = rx.Matches("(X=Customer rating 1.0/5.0)");

   if (matches.Count > 0)
   {
        Console.WriteLine("Matched :" );

        // Get the match output 
        foreach (Match item in matches)
        {
             Console.WriteLine(item.Value);
        }
   }

Here is the regex explanation : https://regex101.com/r/qS0qG3/1

answered Mar 14, 2015 at 12:08

Kavindu Dodanduwa

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