小例子

let yourAttributes = [NSForegroundColorAttributeName: UIColor.blackColor(),NSFontAttributeName: UIFont.systemFontOfSize(15)]
let yourOtherAttributes = [NSForegroundColorAttributeName: UIColor.redColor(),NSFontAttributeName: UIFont.systemFontOfSize(25)]

let partOne = NSMutableAttributedString(string: "This is an example ",attributes: yourAttributes)
let partTwo = NSMutableAttributedString(string: "for the combination of Attributed String!",attributes: yourOtherAttributes)

let combination = NSMutableAttributedString()

combination.appendAttributedString(partOne)
combination.appendAttributedString(partTwo)

Swift 3

combination.append(partOne)
combination.append(partTwo)

然后，组合是您的最终字符串，其中包含由您的属性和yourOtherAttributes提供的格式