Swift连接字符串
示例
将字符串与+运算符连接起来以产生新的字符串：
let name = "John" let surname = "Appleseed" let fullName = name + " " + surname // fullName is "John Appleseed"
使用复合赋值运算符或使用方法附加到可变字符串+=：
let str2 = "there"
var instruction = "look over"
instruction += " " + str2 // instruction is now "look over there"
var instruction = "look over"
instruction.append(" " + str2) // instruction is now "look over there"将单个字符附加到可变字符串：
var greeting: String = "Hello" let exclamationMark: Character = "!" greeting.append(exclamationMark) // produces a modified String (greeting) = "Hello!"
将多个字符附加到可变字符串
var alphabet:String = "我的ABC： "
alphabet.append(contentsOf: (0x61...0x7A).map(UnicodeScalar.init)
.map(Character.init) )
// produces a modified string (alphabet) = "我的ABC： abcdefghijklmnopqrstuvwxyz"appendContentsOf(_:)已重命名为append(_:)。
使用以下命令连接字符串序列以形成新字符串joinWithSeparator(_:)：
let words = ["apple", "orange", "banana"]
let str = words.joinWithSeparator(" & ")
print(str) // "apple & orange & banana"joinWithSeparator(_:)已重命名为joined(separator:)。
在separator默认情况下是空字符串，那么。["a","b","c"].joined()=="abc"