String to Phone Number format on iOS

Question

In my app, I have a string like:

"3022513240"

I want to convert this like:

(302)-251-3240

How can I solve this?

Answer 1

Swift 4.2

Handles 10 and 11 digit phone numbers that may or may not already have formatting or non-digit characters in the string.

Will handle:

• 1234567890, 12345678901, 123 456 7890, 123-456-7890, (123) 456-7890, 1-234-567-8901

Result:

• (999)-999-9999
• 1(999)-999-9999

Code:

extension String {

    /// Handles 10 or 11 digit phone numbers
    ///
    /// - Returns: formatted phone number or original value
    public func toPhoneNumber() -> String {
        let digits = self.digitsOnly
        if digits.count == 10 {
            return digits.replacingOccurrences(of: "(\\d{3})(\\d{3})(\\d+)", with: "($1)-$2-$3", options: .regularExpression, range: nil)
        }
        else if digits.count == 11 {
            return digits.replacingOccurrences(of: "(\\d{1})(\\d{3})(\\d{3})(\\d+)", with: "$1($2)-$3-$4", options: .regularExpression, range: nil)
        }
        else {
            return self
        }
    }

}

extension StringProtocol {

    /// Returns the string with only [0-9], all other characters are filtered out
    var digitsOnly: String {
        return String(filter(("0"..."9").contains))
    }

}

Example:

let num = "1234567890"
let formatted = num.toPhoneNumber()
// Formatted is "(123)-456-7890"