Filter non-digits from string

Question

Using only swift code I cant figure out how to take \"(555) 555-5555\" and return only the numeric values and get \"5555555555\". I need to remove all the parentheses, whit

Answer 1

I had a similar issue but I needed to retain the decimal points. I tweaked the top answer to this:

extension String {

    /// Returns a string with all non-numeric characters removed
    public var numericString: String {
        let characterSet = CharacterSet(charactersIn: "0123456789.").inverted
        return components(separatedBy: characterSet)
            .joined()
    }
}