swift - 如何快速使用NSAttributedString的replaceOccurrences？

在NSAttributed类型语句中，我希望保留现有的属性值并赋予它一个新的属性值。
问题是replacingOccurrences只适用于字符串类型，因为我希望每次单词出现在整个句子中时都给出一个新值。
如果将NSAttributedString更改为字符串类型，则属性值将被删除。我必须保持现有的价值观。
我该怎么做？

最佳答案

为了让这工作顺利进行，
一。首先，您需要找到字符串中存在的所有重复子串的索引。你可以用这个：https://stackoverflow.com/a/40413665/5716829

extension String {
    func indicesOf(string: String) -> [Int] {
        var indices = [Int]()
        var searchStartIndex = self.startIndex

        while searchStartIndex < self.endIndex,
            let range = self.range(of: string, range: searchStartIndex..<self.endIndex),
            !range.isEmpty
        {
            let index = distance(from: self.startIndex, to: range.lowerBound)
            indices.append(index)
            searchStartIndex = range.upperBound
        }

        return indices
    }
}

2.接下来，需要将所需的属性应用于每个索引的子字符串，即。

    let str = "The problem is that replacingOccurrences Hello is only possible for string types, as I want to give Hello a new value every time Hello the word appears in the entire sentence Hello."
    let indices = str.indicesOf(string: "Hello")
    let attrStr = NSMutableAttributedString(string: str, attributes: [.foregroundColor : UIColor.blue])
    for index in indices
    {
        //You can write your own logic to specify the color for each duplicate. I have used some hardcode indices
        var color: UIColor
        switch index
        {
        case 41:
            color = .orange
        case 100:
            color = .magenta
        case 129:
            color = .green
        default:
            color = .red
        }
        attrStr.addAttribute(.foregroundColor, value: color, range: NSRange(location: index, length: "Hello".count))
    }

截图：

如果你还面临任何问题，请告诉我。快乐编码……