快速的IOS文本区域我可以从偏移量或光标中删除文本

Question

var currenTextCount = 0
func textViewDidChange(_ textView: UITextView) {
currentTextCount = currentTextCount+1
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

let startPosition: UITextPosition = writeArea.beginningOfDocument
let selectedRange: UITextRange = writeArea.selectedTextRange!
let cursorPosition = writeArea.offset(from: startPosition, to: selectedRange.start)
i don't know
}

我想删除光标位置处的文本，只要 currenTextCount

或

删除左侧 # 和右侧空格之间的文本

怎么做我不知道

Answer 1

let newPosition:UITextPosition! = writeArea.position(from: selectedRange.start, offset: -currenTextCount)
let nowPosition:UITextPosition! = writeArea.position(from: selectedRange.start, offset: 0)
let tagRange:UITextRange! = writeArea.textRange(from: newPosition, to: nowPosition)
writeArea.replace(tagRange, withText: selectedTag)
writeArea.replace(tagRagne, withText: "String")