swift - 从正则表达式模式匹配返回结果

Question

我有一个字符串(在本示例中为 HTML)，其中包含用于显示体育比赛结果的相同模式。因此，HTML 标签是已知的，但每个游戏的值是未知的。

In Perl, we can do this:

if ( $content =~ /\<\/a\>\<br\>(\d+)\<\/span\>\<br\>(\d+)\-(\d+).+\<\/a\>\<br\>(\d+)\<\/span\>\<br\>(\d+)\-(\d+)/) {
  $visitingTeamScore = $1; // $1 is the 1st matched digit
  $visitingTeamWins = $2; // $2 is the 2nd matched digit
  $visitingTeamLosses = $3; // Etc
  $homeTeamScore = $4;
  $homeTeamWins = $5;
  $homeTeamLosses = $6;
}

which returns the digits inside the parentheses, in this case 6 total integers of varying digit lengths. We can then assign those matches to variables.

---

来自这个问题的答案:Swift Get string between 2 strings in a string ，我有以下 Swift 代码:

extension String {
    func sliceFrom(start: String, to: String) -> String? {
        return (rangeOfString(start)?.endIndex).flatMap { sInd in
            (rangeOfString(to, range: sInd..<endIndex)?.startIndex).map { eInd in
                substringWithRange(sInd..<eInd)
            }
        }
    }
}

let firstMatch = content?.sliceFrom("</a><br>", to: "</span>") // The first integer in the string

问题出现在获取第 4 个整数时，该整数也在 </a\><br> 之间和 </span>所以结果匹配将再次成为第一个数字。

我可以手动计算字符数(这本身并不是一门完美的科学，因为每个整数中的数字可能不同)来做一些丑陋的事情，比如:

let newRawHTML = content![content!.startIndex.advancedBy(15)...content!.startIndex.advancedBy(5)]

另一种可能性是从字符串中删除任何已经匹配的内容，使其在每次后续搜索时更短(我不确定如何实现。)这样做的方法是什么？在 Swift 中有什么方法可以“拔出”火柴吗？

Answer 1

您作为 Perl 示例显示的代码使用了正则表达式。如果模式变得有点复杂，您最好直接使用 NSRegularExpression。

let pattern = "</a><br>(\\d+)</span><br>(\\d+)-(\\d+).+</a><br>(\\d+)</span><br>(\\d+)-(\\d+)"
let regex = try! NSRegularExpression(pattern: pattern, options: [])
if let match = regex.firstMatchInString(content, options: [], range: NSRange(0..<content.utf16.count)) {
    let visitingTeamScore = (content as NSString).substringWithRange(match.rangeAtIndex(1))
    let visitingTeamWins = (content as NSString).substringWithRange(match.rangeAtIndex(2))
    let visitingTeamLosses = (content as NSString).substringWithRange(match.rangeAtIndex(3))
    let homeTeamScore = (content as NSString).substringWithRange(match.rangeAtIndex(4))
    let homeTeamWins = (content as NSString).substringWithRange(match.rangeAtIndex(5))
    let homeTeamLosses = (content as NSString).substringWithRange(match.rangeAtIndex(6))
    //...use the values
}