ios字符串替换为*，最多4个

func replaceSensitiveInfo(string: String) -> String {
    let sensitiveInfo = "敏感信息"
    let replacement = "****"
    
    // 使用正则表达式匹配敏感信息并替换为*
    let regex = try! NSRegularExpression(pattern: sensitiveInfo, options: [])
    let range = NSMakeRange(0, string.count)
    let maskedString = regex.stringByReplacingMatches(in: string, options: [], range: range, withTemplate: replacement)
    
    return maskedString
}