Question

string inputText = "abc13500008888,   *a1c13688886666abc   mm13565685555**" ;

How to use C# Regular Expression to get the match number list?

The rule is that is a 11 continuous number and the first letter is 1.

The results should be:

13500008888
13688886666
13565685555

Answer 1

If the numbers are always 11 digits starting with 1, you can just do

Regex.Matches(inputText, @"1\d{10}");

If you want to match other lengths as well, you can either use + for one or more or {min,} where min is the minimum number of digits you want to match.