字符串初始化
1、初始化
- let someString = "Some string literalvalue"
- let wiseWords = "\"Imagination is moreimportant than knowledge\" -Einstein" let dollarSign = "\x24" // $,
- Unicodescalar U+0024
- let blackHeart = "\u2665" // ♥,
- Unicodescalar U+2665
- let sparklingHeart = "\U0001F496" //
- , Unicode scalarU+1F496
2、空值
- var emptyString = "" //
- 空串初始化
- var anotherEmptyString = String() // 通 过初始化函数初始化
3、空值判断
- if emptyString.isEmpty{
- println("Nothing to see here")
- }
字符串修改
var 声明的可以修改，let 不能修改。
- var variableString = "Horse" variableString+= " and carriage"
- let constantString = "Highlander" constantString += " and another
- Highlander" //错误
字符串插入
- let multiplier = 3
- let message = "\(multiplier) times 2.5 is
- \(Double(multiplier) * 2.5)"
字符串长度
使用 countElements函数。
- let unusualMenagerie = "Koala , Snail, Penguin,Dromedary" println("unusualMenagerie has
- \(countElements(unusualMenagerie))
- characters")
比较字符串相等
- let quotation = "We're a lot alike, you and I."let sameQuotation = "We're a lot alike, youand I."
- if quotation == sameQuotation {
- println("These two strings areconsidered equal")
- }