Swift 4
let combination = NSMutableAttributedString()
var part1 = NSMutableAttributedString()
var part2 = NSMutableAttributedString()
var part3 = NSMutableAttributedString()
let attrRegular = [NSAttributedStringKey.font : UIFont(name: "Palatino-Roman", size: 15)]
let attrBold:Dictionary = [NSAttributedStringKey.font : UIFont(name: "Raleway-SemiBold", size: 15)]
let attrBoldWithColor: Dictionary = [NSAttributedStringKey.font : UIFont(name: "Raleway-SemiBold", size: 15),
NSAttributedStringKey.foregroundColor: UIColor.red]
if let regular = attrRegular as? [NSAttributedStringKey : NSObject]{
part1 = NSMutableAttributedString(string: "first", attributes: regular)
}
if let bold = attrRegular as? [NSAttributedStringKey : NSObject]{
part2 = NSMutableAttributedString(string: "second", attributes: bold)
}
if let boldWithColor = attrBoldWithColor as? [NSAttributedStringKey : NSObject]{
part3 = NSMutableAttributedString(string: "third", attributes: boldWithColor)
}
combination.append(part1)
combination.append(part2)
combination.append(part3)
Attributes list please see here NSAttributedStringKey on Apple Docs