Regex to select a pattern of SubString

Question

What is the syntax for finding and selecting part of a string in Regx C#?

The string could be:

string tdInnerHtml = "<strong> You gained  230 Points </strong> 
                      there is going to be more text and some html code part of this       
                      string <a href=http://google.com>Google it here </a>";

// I want to extract 230 from this string using Regx. 
// The digits (230) vary for each tdInnerHtml. 
// So code would be to look for digits, followed by space, ending with Points

Are you parsing HTML? Use an Html parser, not Regex. That path leads to unspeakable things. — asawyer
– asawyer, Commented Apr 3, 2012 at 18:55
I am using HTML parser but needs to get the the SubString value inside the TD cell. — Shuaib
– Shuaib, Commented Apr 3, 2012 at 18:56
Your parser should understand how to pull attributes and content from an element. Perhaps it's hiding in the documentation? — asawyer
– asawyer, Commented Apr 3, 2012 at 18:57
Please don't prefix your titles with "C#" and such. That's what the tags are for. — John Saunders
– John Saunders, Commented Apr 3, 2012 at 19:10

Walk · Accepted Answer · 2012-04-03 19:42:14Z

4

If the space and the </strong> tag are consistent, you can use the following to get the match there, and will work with strings like: " Pints are between 230-240 Points and You gained 230 Points "

        var match = Regex.Match(tdInnerHtml, @"(?<pts>\d+) Points ?</strong>");
        if (match.Success) {
            int points = Convert.ToInt32(match.Groups["pts"].Value);
            Console.WriteLine("Points: {0}", points);
        }

answered Apr 3, 2012 at 19:42

Walk

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2 Comments

Shuaib Over a year ago

Thanks for the reply. The </strong> is not consistent. "230 Points" could be anywhere inside the string.

Walk Over a year ago

Which part is consistent? Is the "You gained ? Points" consistent?

Tim Lehner · Accepted Answer · 2012-04-03 19:13:16Z

1

I think your regex pattern might be \b[0-9]+\b \bPoints\b.

You might test this at regexpal.

answered Apr 3, 2012 at 19:13

Tim Lehner

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Comments

Brad Christie · Accepted Answer · 2012-04-03 19:49:56Z

1

As long as you're only going for a set of numbers followed by the text Points, Regex can work:

Match match = Regex.Match(tdInnerHtml, @"(?<![\d-])(\d+) Points");
if (match.Success){
  // fetch result
  String pointsString = match.Groups[1].Value;

  // optional: parse to integer
  Int32 points;
  if (Int32.TryParse(pointsString, out points)){
    // you now have an integer value
  }
}

However, if this is in any way related to where the information resides on the page, formatting its surrounded by, or anything else HTML related--heed others' warnings and use an HTML parser.

edited Apr 3, 2012 at 19:49

answered Apr 3, 2012 at 19:13

Brad Christie

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2 Comments

Shuaib Over a year ago

thanks for the reply. If I have a value of: string test = "<strong> Pints are between 230-240 Points and You gained 230 Points </strong>"; your code returns 240. But I want exactly 230 followed by "Points".

Brad Christie Over a year ago

@Shuaib: Use a negative look-behind to assert the \d isn't preceded by a hyphen or number. Basically, change the above code to: @"(?<![\d-])(\d+) Points" -- Example

gregmac · Accepted Answer · 2012-04-03 19:13:31Z

0

The regex is very easy, \d+ Points. Here it is in C#, with a named group capture:

        var match = Regex.Match(tdInnerHtml, "(?<pts>\d+) Points");
        if (match.Success) {
            int points = (int)match.Groups["pts"].Value;
            // do something..
        }

answered Apr 3, 2012 at 19:13

gregmac

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Comments

Kendall Frey · Accepted Answer · 2012-04-03 19:14:00Z

0

string test = "<strong> You gained 230 Points </strong>";
string pattern = @"(\d+)\sPoints";
Regex regex = new Regex(pattern);
Match match = regex.Match(test);
string result = match.Success ? match.Groups[1].Value : "";

answered Apr 3, 2012 at 19:14

Kendall Frey

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