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

Try this:

let string = "(555) 555-5555"
let digitString = string.filter { ("0"..."9").contains($0) }
print(digitString) // 5555555555

Putting in extension:

extension String
{
    var digitString: String { filter { ("0"..."9").contains($0) } }
}

print("(555) 555-5555".digitString) // 5555555555

Answer 2

Swift 3 & 4:

extension String {
    var digits: String {
        return components(separatedBy: CharacterSet.decimalDigits.inverted)
            .joined()
    }
}

Answer 3

You'll want to use NSCharacterSet:

Check out this NSHipster link for Swift and Obj-C implementations: http://nshipster.com/nscharacterset/

Similar example:

var string = "  Lorem    ipsum dolar   sit  amet. "

let components = string.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceCharacterSet()).filter({!isEmpty($0)})

string = join(" ", components)

See: punctuationCharacterSet

Description:

Returns a character set containing the characters in the category of Punctuation. Informally, this set is the set of all non-whitespace characters used to separate linguistic units in scripts, such as periods, dashes, parentheses, and so on.

@Tapani Makes a great suggestion: NSCharacterSet.decimalDigitCharacterSet().invertedSet

Answer 4

Not exactly answered but it looks like a number. I used URLComponents to build the url because it strips out parenthesis and dashes automatically:

var telUrl: URL? {
    var component = URLComponents()
    component.scheme = "tel"
    component.path = "+49 (123) 1234 - 56789"
    return component.url
}

then

UIApplication.shared.open(telUrl, options: [:], completionHandler: nil)

calls +49 123 123456789

Answer 5

In Swift 4 the solution is more nice:

import Foundation

let sourceText = "+5 (555) 555-5555"

let allowedCharset = CharacterSet
    .decimalDigits
    .union(CharacterSet(charactersIn: "+"))

let filteredText = String(sourceText.unicodeScalars.filter(allowedCharset.contains))

print(filteredText) // +55555555555

Answer 6

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()
    }
}