<p>Quick add on requirement in our project.  A field in our DB to hold a phone number is set to only allow 10 characters.  So, if I get passed "(913)-444-5555" or anything else, is there a quick way to run a string through some kind of special replace function that I can pass it a set of characters to allow?</p>

<p>Regex?</p>

Definitely regex:
```
```
string CleanPhone(string phone)
{
    Regex digitsOnly = new Regex(@"[^\d]");   
    return digitsOnly.Replace(phone, "");
}
```
```
or within a class to avoid re-creating the regex all the time:
```
```
private static Regex digitsOnly = new Regex(@"[^\d]");   

public static string CleanPhone(string phone)
{
    return digitsOnly.Replace(phone, "");
}
```
```
Depending on your real-world inputs, you may want some additional logic there to do things like strip out leading 1's (for long distance) or anything trailing an x or X (for extensions).