using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?:(?<=^|[^\d.])(\d{1,3})(?=(?:\d{3})+(?:\D|$))|\G)(\d{3})";
string substitution = @"$1,$2";
string input = @"1 10 100 1000
10000
1000.23
10032323232320.12323232";
RegexOptions options = RegexOptions.Multiline;
Regex regex = new Regex(pattern, options);
string result = regex.Replace(input, substitution);
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx