如何在iOS Swift中替换特定范围内的字符串？

Question

For example string = "Hello @manan123 and @man"

i am doing tagging functionality in textview and i want when user press backspace if word contains @ then whole word will delete not single character.

but i am facing problem while two tagged word have same characters. So in above example when i am trying to delete last word @man then @manan123 also convert to the an123.

Here is my code on textview delegate method

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {

    if text == "" {
        if let selectedRange = textView.selectedTextRange {

            let cursorOffset = textView.offset(from: textView.beginningOfDocument, to: selectedRange.start)
            if let myText = textView.text {
                let index = myText.index(myText.startIndex, offsetBy: cursorOffset)
                let substring = myText[..<index]
                if let lastword = substring.components(separatedBy: " ").last {

                    if lastword.hasPrefix("@") {
                        //Check complete word
                        let completeLastword = myText.components(separatedBy: " ").filter{$0.contains(lastword)}.last
                        textView.text = myText.replacingOccurrences(of: completeLastword!, with: "")
                        return false
                    }
                }
            }
        }
    }

    return true
}

Answer 1

Hi I have updated your code please check it.

if text == "" {
        if let selectedRange = textView.selectedTextRange {
            let cursorOffset = textView.offset(from: textView.beginningOfDocument, to: selectedRange.start)
            if let myText = textView.text {
                let index = myText.index(myText.startIndex, offsetBy: cursorOffset)
                let substring = myText[..<index]
                if let lastword = substring.components(separatedBy: " ").last {

                    if lastword.hasPrefix("@") {
                        var newText = myText
                        let start = newText.index(myText.startIndex, offsetBy: cursorOffset - lastword.count);
                        let end = newText.index(myText.startIndex, offsetBy: (cursorOffset - lastword.count) + lastword.count);
                        newText.replaceSubrange(start..<end, with: "")
                        textView.text = newText
                        return false
                    }
                }
            }
        }
    }

Hope this helps.