Swift字符串类型

字符串初始化

1、初始化

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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

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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

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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。

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var variableString = "Horse" variableString+= " and carriage"

let constantString = "Highlander" constantString += " and another

Highlander" //错误

字符串插入

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let multiplier = 3

let message = "\(multiplier) times 2.5 is

\(Double(multiplier) * 2.5)"

字符串长度

使用 countElements函数。

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let unusualMenagerie = "Koala , Snail, Penguin,Dromedary" println("unusualMenagerie has

\(countElements(unusualMenagerie))

characters")

比较字符串相等

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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")

}

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