Swift 语言基础(2)-字符和字符串
发布时间:2020-12-14 02:17:45 所属栏目:百科 来源:网络整理
导读:字符串字面量 let someString = "Some string literal value" wiseWords = ""Imagination is more important than knowledge" - Einstein" // "Imagination is more important than knowledge" - Einstein dollarSign "x24" // $,Unicode scalar U+0024 b
字符串字面量let someString = "Some string literal value"
wiseWords = ""Imagination is more important than knowledge" - Einstein"
// "Imagination is more important than knowledge" - Einstein dollarSign "x24" // $,Unicode scalar U+0024 blackHeart "u2665" // ?,Unicode scalar U+2665 sparklingHeart "U0001F496" //,□,Unicode scalar U+1F496 初始化空字符串
var emptyString "" // empty string literal
anotherEmptyString = String() // initializer syntax // these two strings are both empty,and are equivalent to each other if emptyString.isEmpty { println("Nothing to see here") } // prints "Nothing to see here"
字符串可变性
variableString "Horse"
+= " and carriage" // variableString is now "Horse and carriage" constantString "Highlander" constantString " and another Highlander" // this reports a compile-time error - a constant string cannot be modified 字符串是值类型
Swift’s String type is a value type. If you create a new String value,that value
is copied when it is passed to a function or method,or when it is assigned to a constant or variable. In each case,a new copy of the existing value is created,and the new copy is passed or assigned,not the original version. 字符处理
for character in "Dog!□" {
(character// D // o // g // ! // □ yenSign: Character "¥" 字符计数
unusualMenagerie "Koala,Snail,Penguin,Dromedary "
"unusualMenagerie has (countElementsunusualMenagerie)) characters"// prints "unusualMenagerie has 40 characters" 连接字符串和字符
string1 "hello"
string2 " there" character1"!" character2"?" stringPlusCharacter + character1 // equals "hello!" stringPlusString // equals "hello there" characterPlusString // equals "!hello" characterPlusCharacter character2 // equals "!?" instruction "look over" += string2 // instruction now equals "look over there" welcome "good morning" character1 // welcome now equals "good morning!" 字符串插补let message = " ( multiplier ) times 2.5 is ( Double ( multiplier ) * 2.5 ) " // message is "3 times 2.5 is 7.5" 字符串比较
quotation "We're a lot alike,you and I."
sameQuotation == println"These two strings are considered equal"// prints "These two strings are considered equal" romeoAndJuliet = [ "Act 1 Scene 1: Verona,A public place", "Act 1 Scene 2: Capulet's mansion""Act 1 Scene 3: A room in Capulet's mansion""Act 1 Scene 4: A street outside Capulet's mansion""Act 1 Scene 5: The Great Hall in Capulet's mansion""Act 2 Scene 1: Outside Capulet's mansion""Act 2 Scene 2: Capulet's orchard""Act 2 Scene 3: Outside Friar Lawrence's cell""Act 2 Scene 4: A street in Verona""Act 2 Scene 5: Capulet's mansion""Act 2 Scene 6: Friar Lawrence's cell"]
var act1SceneCount = 0
fo r scene in scenehasPrefix"Act 1 ") { ++act1SceneCount } println"There are act1SceneCount) scenes in Act 1"// prints "There are 5 scenes in Act 1" mansionCount = 0 cellCount hasSuffix"Capulet's mansion") { mansionCount } else if scene"Friar Lawrence's cell"cellCount } "mansionCountmansion scenes; (cellCountcell scenes") // prints "6 mansion scenes; 2 cell scenes" 字符串大小写转换
normal "Could you help me,please?"
codeUnit dogStringutf8 printcodeUnit"n"// 68 111 103 33 240 159 144 182shouty normaluppercaseString // shouty is equal to "COULD YOU HELP ME,PLEASE?" whispered lowercaseString // whispered is equal to "could you help me,please?" utfutf16 print// 68 111 103 33 55357 56374 scalar unicodeScalars scalarvalue// 68 111 103 33 128054 //□ (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |