swift-字符串中的子字符串

Question

I have some of url string like:

let url1 = " https://abc/help?user_info_id=5#help-article03 "

let url2 = " https://cde?user_info_id=455&artical=4 "

let url3 = " https://ghi/help?user_info_id=5 "

Now i want to get user_info_id from these urls.

url1 return 5, url2 return 455 and url3 return 5

This is my code

func getID(string: String) -> String {
    let range = string.rangeOfString("user_info_id=")
    guard let endIndex = range?.endIndex else { return "" }
    let remain = string.substringFromIndex(endIndex)

    let num = "0123456789"
    var result = ""
    for c in remain.characters {
        if num.containsString(String(c)) {
            result.append(c)
        } else {
            break
        }
    }
    return result
}

Please tell me your idea. Thank you!

Answer 1

Use (NS)URLComponents and filter the query items:

let url1 = "https://cde?user_info_id=455&artical=4"
if let components = NSURLComponents(string: url1),
  let queryItems = components.queryItems,
  let userInfoId = queryItems.filter({$0.name == "user_info_id"}).first where userInfoId.value != nil {
  print(userInfoId.value!)
}