How to remove characters from a string using LINQ

Question

I'm having a String like

XQ74MNT8244A

i nee to remove all the char from the string.

so the output will be like

748244

How to do this? Please help me to do this

Answer 1

Two options. Using Linq on .Net 4 (on 3.5 it is similar - it doesn't have that many overloads of all methods):

string s1 = String.Concat(str.Where(Char.IsDigit));

Or, using a regular expression:

string s2 = Regex.Replace(str, @"\D+", "");

I should add that IsDigit and \D are Unicode-aware, so it accepts quite a few digits besides 0-9, for example "542abc٣٤".
You can easily adapt them to a check between 0 and 9, or to [^0-9]+.

Answer 2

new string("XQ74MNT8244A".Where(char.IsDigit).ToArray()) == "748244"

Answer 3

string value = "HTQ7899HBVxzzxx";
Console.WriteLine(new string(
     value.Where(x => (x >= '0' && x <= '9'))
     .ToArray()));