获取直到特定字符的字符串

var hello = "hello, how are you?"

var hello2 = "hello, how are you @tom?"

我想删除@符号后面的每个字母。

结果应该是

var hello2 = "hello, how are you @tom?"
->
hello2.trimmed() 

print(hello2.trimmed())

-> "hello, how are you"

Update由于我想使用它来链接多个用户并用正确的名称替换@sign后面的空格，因此我总是需要引用最新出现的@sign来替换它。

text3 = "hey i love you @Tom @Marcus @Peter"

最终版本应该是什么样子的示例

开始

var text =“你好@tom@mark@mathias”

我想始终获得文本中最新@符号的索引

扩展 @appzYourLife 答案，以下内容还将在删除 @ 符号后面的所有内容后修剪空白字符。

import Foundation

var str = "hello, how are you @tom"

if str.contains("@") {
    let endIndex = str.range(of: "@")!.lowerBound
    str = str.substring(to: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)
}
print(str) // Output - "hello, how are you"

UPDATE:

为了响应找到最后一次出现的@字符串中的符号并删除它，这是我的处理方法：

var str = "hello, how are you @tom @tim?"
if str.contains("@") {
    //Reverse the string
    var reversedStr = String(str.characters.reversed())
    //Find the first (last) occurance of @
    let endIndex = reversedStr.range(of: "@")!.upperBound
    //Get the string up to and after the @ symbol
    let newStr = reversedStr.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)

    //Store the new string over the original
    str = String(newStr.characters.reversed())
    //str = "hello, how are you @tom"
}

或者查看@appzYourLife 答案使用range(of:options:range:locale:)而不是字面上颠倒字符

var str = "hello, how are you @tom @tim?"
if str.contains("@") {
    //Find the last occurrence of @
    let endIndex = str.range(of: "@", options: .backwards, range: nil, locale: nil)!.lowerBound
    //Get the string up to and after the @ symbol
    let newStr = str.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)

    //Store the new string over the original
    str = newStr
    //str = "hello, how are you @tom"
}

作为额外的好处，以下是我将如何删除所有@从最后一个开始并继续努力：

var str = "hello, how are you @tom and @tim?"
if str.contains("@") {

    while str.contains("@") {
        //Reverse the string
        var reversedStr = String(str.characters.reversed())
        //Find the first (last) occurance of @
        let endIndex = reversedStr.range(of: "@")!.upperBound
        //Get the string up to and after the @ symbol
        let newStr = reversedStr.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)

        //Store the new string over the original
        str = String(newStr.characters.reversed())
    }
    //after while loop, str = "hello, how are you"
}