Swift3.0学习--字符串

遍历

let str = "pig 你是个猪" //str是一个String类型的结构体
        for c in str.characters {
            print(c)
        }
输出:        
p
i
g
 
你
是
个
猪

计算长度

//字节
print(str.lengthOfBytes(using: .utf8)) //输出16 中文3个 16=3+1+3*4
//字符串长度
print(str.characters.count) //输出8
//转NSString
let ocStr = str as NSString //输出8
print(ocStr.length)

字符串拼接

let name = "猪"
let age = 19
let title:String? = "BOSS"
let point = CGPoint(x: 100, y: 100)
let str = "\(name)\(age)\(title ?? "")\(point)"
print(str) // 输出:猪19BOSS(100.0, 100.0)
let h = 8
let m = 6
let s = 10
let dateStr = "\(h):\(m):\(s)"
let dateStr1 = String(format: "%02d:%02d:%02d", h,m,s);
print(dateStr,dateStr1) //输出:8:6:10 08:06:10

字符串截取

//常用的就是转为NSString
let str = "一二三四五六七"
let ocStr = str as NSString
let s1 = ocStr.substring(with: NSMakeRange(2, 3))
print(s1) //输出:三四五

2017-06-06