Are there any analogues of [NSString stringWithFormat:] for NSAttributedString

Question

Usually I build app interface in interface builder. Sometimes design requires to use attributed strings (fonts, colors and etc.). It\'s easy to configure if string is static

Answer 1

Here is a Swift 4 extension based on TheJeff's answer (corrected for multiple substitutions). It is restricted to substituting placeholders with NSAttributedString's:

public extension NSAttributedString {
    convenience init(format: NSAttributedString, args: NSAttributedString...) {
        let mutableNSAttributedString = NSMutableAttributedString(attributedString: format)

        var nsRange = NSString(string: mutableNSAttributedString.string).range(of: "%@")
        var param = 0
        while nsRange.location != NSNotFound {
            guard args.count > 0, param < args.count else {
                fatalError("Not enough arguments provided for \(format)")
            }

            mutableNSAttributedString.replaceCharacters(in: nsRange, with: args[param])
            param += 1
            nsRange = NSString(string: mutableNSAttributedString.string).range(of: "%@")
        }

        self.init(attributedString: mutableNSAttributedString)
    }
}