Swift:字符串范围截取操作

1.字符串范围截取(prefix;suffix)：

//字符串范围截取

let num = "123.45"

let deRange = num.range(of: ".")

//FIXME:按某个字符串截取

//截取小数点前字符(不包含小数点)  123

let wholeNumber = num.prefix(upTo: deRange!.lowerBound)

//截取小数点后字符(不包含小数点) 45

let backNumber = num.suffix(from: deRange!.upperBound)

//截取小数点前字符(包含小数点) 123.

let wholeNumbers = num.prefix(upTo: deRange!.upperBound)

//截取小数点后字符(包含小数点) .45

let backNumbers = num.suffix(from: deRange!.lowerBound)

2.字符串范围截取操作

var str = "Hello, qqq"

var index = str.index(of: ",")//得到“,”在字符串中的位置

let str3 = str[index!...]//获取","后的所有字符（包括",")

//Swift 3.0

let greeting = str[str.startIndex..

3.删除与字符串替换

//FIXME:删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)

//替换字符串  Hnewo

var sig = "H123456o"

sig.replacingCharacters(in: startIndex...endIndex, with: "123456")

4.append方法应用：

var resultArray: [String] = []

resultArray.append(contentsOf: [str1, str2,"123456"])

resultArray.append("hahahaha")

print(resultArray)

输出结果：["josh", "joshwang", "123456", "hahahaha"]

5.contains方法应用：

let str1 = "qqq"

let str2 = "qqqwang"

str1.contains(str2)  //false

str2.contains(str1)  //true