Question

通过使用Jsoup我从网站解析HTML以填充ArrayList我需要从网站获取的内容。所以现在我有一个充满字符串的ArrayList。我想在该列表中找到包含特定字符串的索引。例如，我知道列表中的某个地方，在某个索引中，有字符串（文字）“Claude”，但我似乎无法创建任何代码来查找contains“Claude”中的索引。 ArrayList ...这是我尝试过但返回-1（未找到）：

ArrayList < String > list = new ArrayList < String > ();
String claude = "Claude";

Document doc = null;
try {
    doc = Jsoup.connect("http://espn.go.com/nhl/team/stats/_/name/phi/philadelphia-flyers").get();
} catch (IOException e) {
    e.printStackTrace();
}
for (Element table: doc.select("table.tablehead")) {
    for (Element row: table.select("tr")) {
        Elements tds = row.select("td");
        if (tds.size() > 6) {
            String a = tds.get(0).text() + tds.get(1).text() + tds.get(2).text() + tds.get(3).text() + tds.get(4).text() + tds.get(5).text() + tds.get(6).text();

            list.add(a);

            int claudesPos = list.indexOf(claude);
            System.out.println(claudesPos);
        }
    }
}

Answer 1

你让String.indexOf和List.indexOf感到困惑。考虑以下列表：

list[0] = "Alpha Bravo Charlie"
list[1] = "Delta Echo Foxtrot"
list[2] = "Golf Hotel India"

list.indexOf("Foxtrot") => -1
list.indexOf("Golf Hotel India") => 2
list.get(1).indexOf("Foxtrot") => 11

所以：

if (tds.size() > 6) {
  // now the string a contains the text of all of the table cells joined together
  String a = tds.get(0).text() + tds.get(1).text() + tds.get(2).text() +
      tds.get(3).text() + tds.get(4).text() + tds.get(5).text() + tds.get(6).text();

  // now the list contains the string
  list.add(a);

  // now you're looking in the list (which has all the table cells' items)
  // for just the string "Claude", which doesn't exist
  int claudesPos = list.indexOf(claude);
  System.out.println(claudesPos);

  // but this might give you the position of "Claude" within the string you built
  System.out.println(a.indexOf(claude));
}

for (int i = 0; i < list.size(); i += 1) {
  if (list.get(i).indexOf(claude) != -1) {
    // list.get(i).contains(claude) works too
    // and this will give you the index of the string containing Claude
    // (but not the position within that string)
    System.out.println(i);
  }
}

Answer 2

First check whether it is an instance of String then get index

if (x instanceof String) {
    ...
}

for (int i = 0; i < list.size(); i++) {
    if (list.get(i).getX() == someValue) { // Or use equals() if it actually returns an Object.
        // Found at index i. Break or return if necessary.
    }
}

在包含字符串的ArrayList中查找索引

2 个答案: