Get the specific number from string in view of beginning whole number in c#

Question

I am attempting to get the Match an esteem from a string. I have to get two sorts of numbers from the given string. Number begins from 5 took after by 6 digits. ex(5******) and begins from 1 took after by 5 digits(1*****).

I use the following regexex:

(5)[\d]{6} 
(1)[\d]{5}

Code:

  var sampleId5 = Regex.Match(input, @"(5)[\d]{6}");
  if (sampleId5.Success)
  {
      string test = sampleId5.Value;
  }

  var sampleId1 = Regex.Match(input, @"(1)[\d]{5}");
  if (sampleId1.Success)
  {
      string test1 = sampleId1.Value;
  }

Issue here is, whether I pass 5106542 it is returning both coordinated results.

I attempted this (^5)[\d]{6} too. be that as it may, its not working.

I require just 5******. Any help would be truly valued.

Answer 1

The problem is that your expressions do not make any requirements about the placement of the match, so they find matches in the middle.

If you need to find stand-alone numbers that fit your criteria, add \b on both sides of your expressions to ensure that there are no letters/digits on either side:

var sampleId1 = Regex.Match(input, @"\b(1)[\d]{5}\b");
//                                   ^^          ^^

Now that the expression considers only isolated sequences of digits, 5106542 is not going to match, because the matched sequence is in the middle.