Question

I want to format an integer so that it appears first with the 1000’s separator (,), but after that with 100’s separator (,)

Input:123456789
Output: 12,34,56,789

Answer 1

You can create a NumberFormatInfo that has a NumberGroupSizes array that gives you that format:

NumberFormatInfo info = new NumberFormatInfo();
info.NumberGroupSizes = new int[]{3,2};

Console.WriteLine(123456789.ToString("#,#", info));

Output:

12,34,56,789