/*
split(" ")按照" "分割字符串，对每个分割出来的字符创建为String
lazy是延迟调用
map(String.init) == map {String($0)}
后者必须使用{}是因为调用了参数$0
*/
let s = "1 2 3 4 5"
let s2 = s.characters.split(" ").lazy.map(String.init)
let s3 = s.characters.split(" ").map {String($0)}
s2.first
s3.first
let s4 = s.characters.split(s.lengthOfBytesUsingEncoding(NSUTF8StringEncoding), allowEmptySlices: true) { (char) -> Bool in
return char == " "
}.map(String.init)
s4.first
//字符串中替换字符
let ss = "1?2?3?"
let ss2 = ss.stringByReplacingOccurrencesOfString("?", withString: "/", options: .LiteralSearch, range: nil)
ss2
let sss = " 123 "
//字符串中过滤字符
let ss3 = sss.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
ss3
//将数组中元素拼接为字符串
let ssss = ["1", "2", "3"]
let ss4 = ssss.joinWithSeparator("/")
