查找list中的重复数据，并得到不重复数据索引位置

Posted 2020-11-24 sunbinary

public static void main(String[] args) {
    List<String> strLs = new ArrayList<String>();
    strLs.add("香蕉");
    strLs.add("苹果");
    strLs.add("苹果");
    strLs.add("橘子");
    strLs.add("橘子");
    strLs.add("橘子");
    strLs.add("哈密瓜");
    strLs.add("西瓜");

    same(strLs);
}

public static List<Integer> same(List<String> list) {
    Map<String, String> map = new HashMap<String, String>();
    for (int i = 0; i < list.size(); i++) {
        String key = list.get(i);
        String old = map.get(key);
        if (old != null) {
            map.put(key, old + "," + (i + 1));
        } else {
            map.put(key, "" + (i + 1));
        }
    }
    Iterator<String> it = map.keySet().iterator();
    List<Integer> list2 = new ArrayList<>();
    StringBuffer buffer = new StringBuffer();
    while (it.hasNext()) {
        String key = it.next();
        String value = map.get(key);
        if (value.indexOf(",") == -1) {
            System.out.println(key + "不重复,行： " + value);
            buffer.append(value).append(",");
        }
    }
    String string = buffer.deleteCharAt(buffer.length()-1).toString();
    
    String[] split = string.split(",");
    for (String string2 : split) {
        list2.add(Integer.parseInt(string2.trim()));
    }
    Collections.sort(list2);
    return list2;
}