1.字符串范圍截取(prefix;suffix)：
//字符串范圍截取
let num = "123.45"
let deRange = num.range(of: ".")
//FIXME:按某個(gè)字符串截取
//截取小數(shù)點(diǎn)前字符(不包含小數(shù)點(diǎn))? 123
let wholeNumber = num.prefix(upTo: deRange!.lowerBound)
//截取小數(shù)點(diǎn)后字符(不包含小數(shù)點(diǎn)) 45
let backNumber = num.suffix(from: deRange!.upperBound)
//截取小數(shù)點(diǎn)前字符(包含小數(shù)點(diǎn)) 123.
let wholeNumbers = num.prefix(upTo: deRange!.upperBound)
//截取小數(shù)點(diǎn)后字符(包含小數(shù)點(diǎn)) .45
let backNumbers = num.suffix(from: deRange!.lowerBound)
2.字符串范圍截取操作
var str = "Hello, qqq"
var index = str.index(of: ",")//得到“,”在字符串中的位置
let str3 = str[index!...]//獲取","后的所有字符（包括",")
//Swift 3.0
let greeting = str[str.startIndex..
3.刪除與字符串替換
//FIXME:刪除字符串中的某部分 Ho
var str5 = "Hello"
let startIndex = str.index(str.startIndex, offsetBy: 1)
let endIndex = str.index(str.startIndex, offsetBy: 3)
str5.removeSubrange(startIndex...endIndex)
//替換字符串? Hnewo
var sig = "H123456o"
sig.replacingCharacters(in: startIndex...endIndex, with: "123456")
4.append方法應(yīng)用：
var resultArray: [String] = []
resultArray.append(contentsOf: [str1, str2,"123456"])
resultArray.append("hahahaha")
print(resultArray)
輸出結(jié)果：["josh",?"joshwang",?"123456",?"hahahaha"]
5.contains方法應(yīng)用：
let str1 = "qqq"
let str2 = "qqqwang"
str1.contains(str2)? //false
str2.contains(str1)? //true
