使用正则表达式查找模式匹配的第n个实例

Question

Given the String:

<td>4</td><td>punz of damage</td><td><img src='images/no.png'></img></td><td>May 26, 2015 10:28:12 PM</td><td>30</td><td>Nov 26, 2017 10:28:12 PM</td>

I would like to be able to return only the value between the second element.

How would I accomplish this? I have the following so far:

    private static Pattern p = Pattern.compile("<td>(.+?)</td>");

public static String getName(String in) {
    Matcher m = p.matcher(in);

    if (m.matches()) {
        return m.group(1);
    } else {
        return null;
    }
}

Answer 1

Use matcher.find() in a loop instead of matches and keep a counter:

private static Pattern p = Pattern.compile("<td>(.+?)</td>");

public static String getName(String in) {
    Matcher m = p.matcher(in);

    for (i=0; i<1 && m.find(); i++);

    if (i==0) {
        return null;
    } else {
        return m.group(1);
    }
}

Caution: Parsing HTML/XML using regex can be error prone.