如何在Swift 4中使用字符串子字符串';子串(to:)&x27;已弃用:请使用带';部分范围为';操作人员
我用Swift 3编写了以下简单代码:如何在Swift 4中使用字符串子字符串';子串(to:)&x27;已弃用:请使用带';部分范围为';操作人员,swift,swift4,Swift,Swift4,我用Swift 3编写了以下简单代码: let str = "Hello, playground" let index = str.index(of: ",")! let newStr = str.substring(to: index) 从Xcode 9 beta 5中,我得到以下警告: “substring(to:)”已被弃用:请使用带有“部分范围从”运算符的String切片下标 如何在Swift 4中使用部分范围为的切片下标?您应该将一侧保留为空,因此命名为“部分范围” 请记住,这些范围
let str = "Hello, playground"
let index = str.index(of: ",")!
let newStr = str.substring(to: index)
从Xcode 9 beta 5中,我得到以下警告:
“substring(to:)
”已被弃用:请使用带有“部分范围从”运算符的String
切片下标
如何在Swift 4中使用部分范围为的切片下标?您应该将一侧保留为空,因此命名为“部分范围” 请记住,这些范围运算符返回一个子字符串
。如果要将其转换为字符串,请使用string
的初始化功能:
let newStr = String(str[..<index])
let newStr=String(str[…Swift3和Swift4中的uppercasedFirstCharacter
便利属性示例
属性uppercasedFirstCharacterNew
演示如何在Swift4中使用字符串切片下标
extension String {
public var uppercasedFirstCharacterOld: String {
if characters.count > 0 {
let splitIndex = index(after: startIndex)
let firstCharacter = substring(to: splitIndex).uppercased()
let sentence = substring(from: splitIndex)
return firstCharacter + sentence
} else {
return self
}
}
public var uppercasedFirstCharacterNew: String {
if characters.count > 0 {
let splitIndex = index(after: startIndex)
let firstCharacter = self[..<splitIndex].uppercased()
let sentence = self[splitIndex...]
return firstCharacter + sentence
} else {
return self
}
}
}
let lorem = "lorem".uppercasedFirstCharacterOld
print(lorem) // Prints "Lorem"
let ipsum = "ipsum".uppercasedFirstCharacterNew
print(ipsum) // Prints "Ipsum"
扩展字符串{
公共变量uppercasedFirstCharacterOld:字符串{
如果characters.count>0{
让splitIndex=索引(在:startIndex之后)
让firstCharacter=substring(to:splitIndex).uppercased()
让句子=子字符串(from:splitIndex)
返回第一个字符+句子
}否则{
回归自我
}
}
公共变量uppercasedFirstCharacterNew:字符串{
如果characters.count>0{
让splitIndex=索引(在:startIndex之后)
让firstCharacter=self[…也可以通过以下方式将代码转换为Swift 4:
let str = "Hello, playground"
let index = str.index(of: ",")!
let substr = str.prefix(upTo: index)
您可以使用以下代码创建新字符串:
let newString = String(str.prefix(upTo: index))
子字符串(从:索引)转换为[index…]
检查样品
let text = "1234567890"
let index = text.index(text.startIndex, offsetBy: 3)
text.substring(from: index) // "4567890" [Swift 3]
String(text[index...]) // "4567890" [Swift 4]
一些有用的扩展:
extension String {
func substring(from: Int, to: Int) -> String {
let start = index(startIndex, offsetBy: from)
let end = index(start, offsetBy: to - from)
return String(self[start ..< end])
}
func substring(range: NSRange) -> String {
return substring(from: range.lowerBound, to: range.upperBound)
}
}
扩展字符串{
func子字符串(from:Int,to:Int)->String{
让开始=索引(开始索引,偏移:起始)
让结束=索引(开始,偏移:到-从)
返回字符串(self[start..字符串{
返回子字符串(从:range.lowerBound到:range.upperBound)
}
}
将子字符串(Swift 3)转换为字符串切片(Swift 4)
Swift 3、4中的示例:
let newStr = str.substring(to: index) // Swift 3
let newStr = String(str[..<index]) // Swift 4
let range=firstIndex..Swift 5,4
用法
let text=“你好,世界”
text[0]//H
文本[…3]/“地狱”
文本[6..字符{
self[索引(at:value)]
}
}
公共扩展字符串{
下标(值:NSRange)->子字符串{
self[value.lowerBound..Substring{
self[索引(at:value.lowerBound)…索引(at:value.upperBound)]
}
下标(值:CountableRange)->子字符串{
self[index(at:value.lowerBound)…子字符串{
自[…子串{
self[…索引(at:value.upperBound)]
}
下标(值:PartialRangeFrom)->子字符串{
self[索引(at:value.lowerBound)…]
}
}
专用扩展字符串{
func索引(偏移量:Int)->String.index{
索引(startIndex,offsetBy:offset)
}
}
在编程时,我经常使用带有普通A-Za-z和0-9的字符串。不需要复杂的索引操作。此扩展基于普通的旧左/中/右函数
extension String {
// LEFT
// Returns the specified number of chars from the left of the string
// let str = "Hello"
// print(str.left(3)) // Hel
func left(_ to: Int) -> String {
return "\(self[..<self.index(startIndex, offsetBy: to)])"
}
// RIGHT
// Returns the specified number of chars from the right of the string
// let str = "Hello"
// print(str.left(3)) // llo
func right(_ from: Int) -> String {
return "\(self[self.index(startIndex, offsetBy: self.length-from)...])"
}
// MID
// Returns the specified number of chars from the startpoint of the string
// let str = "Hello"
// print(str.left(2,amount: 2)) // ll
func mid(_ from: Int, amount: Int) -> String {
let x = "\(self[self.index(startIndex, offsetBy: from)...])"
return x.left(amount)
}
}
扩展字符串{
//左
//从字符串左侧返回指定数量的字符
//让str=“你好”
//打印(str.left(3))//Hel
func left(u-to:Int)->字符串{
return“\(self[…这是我的解决方案,没有警告,没有错误,但很完美
let redStr: String = String(trimmStr[String.Index.init(encodedOffset: 0)..<String.Index.init(encodedOffset: 2)])
let greenStr: String = String(trimmStr[String.Index.init(encodedOffset: 3)..<String.Index.init(encodedOffset: 4)])
let blueStr: String = String(trimmStr[String.Index.init(encodedOffset: 5)..<String.Index.init(encodedOffset: 6)])
let redStr:String=String(trimmStr[String.Index.init(encodedOffset:0)…
extension String {
func sliceByCharacter(from: Character, to: Character) -> String? {
let fromIndex = self.index(self.index(of: from)!, offsetBy: 1)
let toIndex = self.index(self.index(of: to)!, offsetBy: -1)
return String(self[fromIndex...toIndex])
}
func sliceByString(from:String, to:String) -> String? {
//From - startIndex
var range = self.range(of: from)
let subString = String(self[range!.upperBound...])
//To - endIndex
range = subString.range(of: to)
return String(subString[..<range!.lowerBound])
}
}
扩展字符串{
func sliceByCharacter(from:Character,to:Character)->字符串{
设fromIndex=self.index(self.index(of:from)!,偏移量:1)
设toIndex=self.index(self.index(of:to)!,偏移量:-1)
返回字符串(self[从索引…到索引])
}
func sliceByString(from:String,to:String)->String{
//From-startIndex
var范围=自身范围(of:from)
让subString=String(self[range!.upperBound…)
//结束索引
范围=子字符串。范围(of:to)
返回字符串(子字符串[…使用Swift 4从字符串创建子字符串(前缀和后缀):
如果要在两个索引之间生成子字符串,请使用:
let substring1=string[startIndex…endIndex]//包括endIndex
让subString2=string[startIndex..您可以使用类字符串的扩展创建自定义子字符串方法,如下所示:
extension String {
func subString(startIndex: Int, endIndex: Int) -> String {
let end = (endIndex - self.count) + 1
let indexStartOfText = self.index(self.startIndex, offsetBy: startIndex)
let indexEndOfText = self.index(self.endIndex, offsetBy: end)
let substring = self[indexStartOfText..<indexEndOfText]
return String(substring)
}
}
扩展字符串{
func子字符串(startIndex:Int,endIndex:Int)->String{
让end=(endIndex-self.count)+1
让indexStartOfText=self.index(self.startIndex,offsetBy:startIndex)
让indexEndOfText=self.index(self.endIndex,offsetBy:end)
让substring=self[indexStartOfText..希望这对您的帮助不大:-
var string = "123456789"
如果您想在某个特定索引后使用子字符串
var indexStart = string.index(after: string.startIndex )// you can use any index in place of startIndex
var strIndexStart = String (string[indexStart...])//23456789
如果在删除末尾的一些字符串后需要一个子字符串
var indexEnd = string.index(before: string.endIndex)
var strIndexEnd = String (string[..<indexEnd])//12345678
Swift 4/5中的较短版本:
var string = "123456"
string = String(string.prefix(3)) //"123"
string = String(string.suffix(3)) //"456"
使用此方法,您可以获得字符串的特定范围。您需要传递起始索引,然后传递所需的字符总数
extension String{
func substring(fromIndex : Int,count : Int) -> String{
let startIndex = self.index(self.startIndex, offsetBy: fromIndex)
let endIndex = self.index(self.startIndex, offsetBy: fromIndex + count)
let range = startIndex..<endIndex
return String(self[range])
}
}
扩展字符串{
func子字符串(fromIndex:Int,count:Int)->字符串{
设startIndex=self.index(self.startIndex,offsetBy:fromIndex)
让endIndex=self.index(self.startIndex,offsetBy:fromIndex+count)
让range=startIndex..希望这会有帮助
extension String {
func getSubString(_ char: Character) -> String {
var subString = ""
for eachChar in self {
if eachChar == char {
return subString
} else {
subString += String(eachChar)
}
}
return subString
}
}
let str: String = "Hello, playground"
print(str.getSubString(","))
迅捷5
(Java的子字符串方法):
var str=“你好,游乐场”
设indexcut=str.firstIndex(of:“,”)
print(String)(str[…str[…使用字符串插值和一个单独的Substring
可能会有点混淆,因为您真正想要完成的是String
初始化:let newStr=String(str[…更新代码,其中我的'index'值只是一个整数
prefix , suffix : ilike
prefix i, suffix : like
prefix il, suffix : ike
prefix ili, suffix : ke
prefix ilik, suffix : e
prefix ilike, suffix :
let substring1 = string[startIndex...endIndex] // including endIndex
let subString2 = string[startIndex..<endIndex] // excluding endIndex
extension String {
func subString(startIndex: Int, endIndex: Int) -> String {
let end = (endIndex - self.count) + 1
let indexStartOfText = self.index(self.startIndex, offsetBy: startIndex)
let indexEndOfText = self.index(self.endIndex, offsetBy: end)
let substring = self[indexStartOfText..<indexEndOfText]
return String(substring)
}
}
var string = "123456789"
var indexStart = string.index(after: string.startIndex )// you can use any index in place of startIndex
var strIndexStart = String (string[indexStart...])//23456789
var indexEnd = string.index(before: string.endIndex)
var strIndexEnd = String (string[..<indexEnd])//12345678
var indexWithOffset = string.index(string.startIndex, offsetBy: 4)
var string = "123456"
string = String(string.prefix(3)) //"123"
string = String(string.suffix(3)) //"456"
extension String{
func substring(fromIndex : Int,count : Int) -> String{
let startIndex = self.index(self.startIndex, offsetBy: fromIndex)
let endIndex = self.index(self.startIndex, offsetBy: fromIndex + count)
let range = startIndex..<endIndex
return String(self[range])
}
}
extension String {
func getSubString(_ char: Character) -> String {
var subString = ""
for eachChar in self {
if eachChar == char {
return subString
} else {
subString += String(eachChar)
}
}
return subString
}
}
let str: String = "Hello, playground"
print(str.getSubString(","))
extension String {
func subString(from: Int, to: Int) -> String {
let startIndex = self.index(self.startIndex, offsetBy: from)
let endIndex = self.index(self.startIndex, offsetBy: to)
return String(self[startIndex..<endIndex])
}
}
var str = "Hello, Nick Michaels"
print(str.subString(from:7,to:20))
// print Nick Michaels
var str = "Hello, playground"
let indexcut = str.firstIndex(of: ",")
print(String(str[..<indexcut!]))
print(String(str[indexcut!...]))