Swift字符串常用操作总结

版本2：增加了Swift 2.0的语法，与Swift 1.2的语法相比，主要是：advance方法变成了advancedBy方法（但不是简单替换）；没有了count方法，count(str)需要变成str.characters.count等。
字符串的定义
var str1="hello, mandarava." //字符串变量let str2="hello, mandarava." //字符串常量let str3="" //空字符串let str4=String() //空字符串
字符的定义
var char1:Character="m" //字符变量let char2:Character="m" //字符常量
字符串的连接
let str1="hello, "let str2="mandarava."let str3=str1+str2 //=连接str1、str2//str3="hello, mandarava."//----------------------------------------let str4="\(str1)\(str2)" //=连接str1、str2//str4="hello, mandarava."//----------------------------------------let strArray=["apple", "orange", "cherry"]let joinStr=",".join(strArray)//joinStr="apple,orange,cherry"
字符串与字符的连接
let char1:Character="o"var str1="hell"let str2=str1+String(char1)//str2="hello"//----------------------------------------let str3="\(str1)\(char1)"//str3="hello"//----------------------------------------str1.append(char1)//str1="hello"
字符串与其它类型值的连接
let xx=10let yy=10.8let str1="\(xx)+\(yy)=?"//str1="10+10.8=?"//----------------------------------------let str2=String(format: "%i+%.1f=?", xx, yy)//str2="10+10.8=?"
字符串枚举字符
//Swift 1.2let str="mandarava"for ch in str{ println(ch)}//-----------------------//Swift 2.0let str="mandarava"for ch in str.characters{ print(ch)}
获取字符串中指定索引处的字符
let str="Mandarava"let chr=str[advance(str.startIndex,2)] //Swift 1.2 //chr:Character="n"let chr=str[str.startIndex.advancedBy(2)] //Swift 2.0 //chr:Character="n"
计算字符串长度length
let str="@鳗驼螺"let len1=count(str) //swift 1.2 //=4 let len2=str.characters.count //swift 2.0 //=4 let blen=str.lengthOfBytesUsingEncoding(NSUTF8StringEncoding) //=10
字符串比较
let str1="hello,"let str2="mandarava."let str3="hello,mandarava."let comp1 = str1==str2 //falselet comp2 = str1+str2 == str3 //truelet comp3 = str1 < str2 //truelet comp4 = str1 != str2 //true
是否包含子串contains
let str1="hello,mandarava."let str2="mandarava"let range=str1.rangeOfString(str2)if range != nil{ //包含}
查找子串indexof
var str="hi,Mandarava."let range=str.rangeOfString("Mandarava", options: NSStringCompareOptions.allZeros) //Swift 1.2let range=str.rangeOfString("Mandarava", options: NSStringCompareOptions()) //Swift 2.0let startIndex=range?.startIndex //=3
首字母大写capitalized
var str1="mandarava is a flower."str1.capitalizedString//str1="Mandarava Is A Flower.
转换为大写字母uppercase
var str1="hello, mandarava."str1=str1.uppercaseString//str1="HELLO, MANDARAVA."
转换为小写字母lowercase
var str1="HELLO, MANDARAVA."str1=str1.lowercaseString//str1="hello, mandarava."
截取字符串substring
let str1="hello,mandarava."let str2=str1.substringFromIndex(advance(str1.startIndex, 6)) //Swift 1.2let str2=str1.substringFromIndex(str1.startIndex.advancedBy(6)) //Swift 2.0//str2="mandarava."//----------------------------------------let str3=str1.substringToIndex(advance(str1.startIndex, 5)) //Swift 1.2let str3=str1.substringToIndex(str1.startIndex.advancedBy(5)) //Swift 2.0//str3="hello"//----------------------------------------let range=Range<String.Index>(start: advance(str1.startIndex, 6), end: advance(str1.endIndex, -1)) //Swift 1.2let range=Range<String.Index>(start: str1.startIndex.advancedBy(6), end: str1.endIndex.advancedBy(-1)) //Swift 2.0let str4=str1.substringWithRange(range)//str4="mandarava"
字符串修剪trim
let str1=" mandarava.\n "let str2=str1.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())//str2="mandarava."//----------------------------------------let str3=str1.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())//str3="mandarava.\n"//----------------------------------------let charset=NSCharacterSet(charactersInString:" \n")let str4=str1.stringByTrimmingCharactersInSet(charset)//str4="mandarava."
字符串的分解子串split
var str1="boy, girl, man, woman"let str1Array=str1.componentsSeparatedByString(",")//str1Array=["boy", " girl", " man", " woman"]var str2="boy,girl,man 10 20 30"let charset=NSCharacterSet(charactersInString:", ")let str2Array=str2.componentsSeparatedByCharactersInSet(charset)//str2Array=["boy", "girl", "man", "10", "20", "30"]
字符串替换replace
var str1="My name is Mandarava."let subRange=Range(start: str1.startIndex, end: advance(str1.startIndex, 2)) //Swift 1.2let subRange=Range(start: str1.startIndex, end: str1.startIndex.advancedBy(2)) //Swift 2.0str1.replaceRange(subRange, with: "Your")//str1="Your name is Mandarava."var str2="hello, Mandarava."str2=str2.stringByReplacingOccurrencesOfString("Mandarava", withString: "鳗驼螺")//str2="hello, 鳗驼螺."str2=str2.stringByReplacingOccurrencesOfString("鳗驼螺", withString: "Mandarava", options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil)//str2="hello, Mandarava."
string转换为Int/Long/Float/Double/Bool等
var str1="100"var i=str1.toInt()! //Swift 1.2 //=100 var i=(str1 as NSString).integerValue //Swift 2.0 //=100var i=(str1 as NSString).intValue //=100var l=(str1 as NSString).longLongValue //=100var str2="10.8"var f=(str2 as NSString).floatValue //=10.8var d=(str2 as NSString).doubleValue //=10.8var str3="true"var b=(str3 as NSString).boolValue //=true
其它想到再补充！如有错误欢迎指正！
by Mandarava（鳗驼螺）
        
                
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作者：鳗驼螺
链接：http://www.jianshu.com/p/52e7580166ff
來源：简书
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