Matching numbers with regular expressions — only digits and commas

Question

I can\'t figure out how to construct a regex for the example values:

123,456,789
-12,34
1234
-8

Could you help me?

Answer 1

If you only want to allow digits and commas, ^[-,0-9]+$ is your regex. If you also want to allow spaces, use ^[-,0-9 ]+$.

However, if you want to allow proper numbers, better go with something like this:

^([-+] ?)?[0-9]+(,[0-9]+)?$

or simply use .net's number parser (for the various NumberStyles, see MSDN):

try {
    double.Parse(yourString, NumberStyle.Number);
}
catch(FormatException ex) {
    /* Number is not in an accepted format */
}