Swift Tips(持续更新)

1、NSMutableAttributedString to String

var attributedString = NSMutableAttributedString(string: "hello, world!")
var str = attributedString.string

2、swift中的交换元素
使用swift中的Tuple（多元组）

var a = 10
var b = 20
(a,b) = (b,a)
print(a,b)//a = 20,b = 10

3、判断字符串相等

var str = "hello, world!"
if str == "hello, world!" {
    print("equal")
}

4、获取字符串长度

var str = "hello, world!"
print(str.characters.count)

5、transform

self.textField.transform = CGAffineTransform.init(translationX: 0, y: 100)

6、character to string

let greeting = "Guten Tag!"
let index = greeting.index(greeting.startIndex, offsetBy: 0)
var myStr:String = String(greeting[index])

7、获得键盘的高度

if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
    let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
    // ...
}