改变label部分文字的颜色

//根据开发需要，有很多时候我们需要改变一个label中部分文字的颜色，不要跟我说多来几个label不就行了，我自能呵呵了，下面我们用一个方法搞定！
看代码：（swift）

import UIKit

class ViewController: UIViewController {

@IBOutlet var label: UILabel!
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    setupAttributeString("大唐国际大厦", highlightText: "大唐")

}
//MARK  富文本部分字体飘灰
func setupAttributeString(text : NSString, highlightText : NSString) -> NSMutableAttributedString {
    let hightlightTextRange = text.rangeOfString(highlightText as String)
    let attributeStr = NSMutableAttributedString.init(string: text as String)
    attributeStr.addAttributes([NSForegroundColorAttributeName:UIColor.blueColor(),NSFontAttributeName:UIFont.systemFontOfSize(14)], range: hightlightTextRange)
    self.label?.lineBreakMode = .ByCharWrapping
    self.label?.attributedText = attributeStr
    return attributeStr
}

}