java集合2種分組方式

  /**
     * @param list 被分組集合
     * @param n    每組個數
     * @return
     */
    public static List <List> groupList(List list, int n) {
        List <List> result = new ArrayList <> ();
        int remainder = list.size () % n; //(先計算出餘數)
        int number = list.size () / n; //然後是商
        if (0 != remainder) {
            number = number + 1;
        }
        for (int i = 0; i < number; i++) {
            List value = null;
            if (i < number - 1) {
                value = list.subList (i * n, (i + 1) * n);
            } else {
                value = list.subList (n * (number - 1), list.size ());
            }
            result.add (value);
        }
        return result;
    }

 /**
     * 將集合分成n組
     *
     * @param list 被分組集合
     * @param n    拆分成n組
     * @return
     */
    public static List <List> groupList(List list, int n) {
        List <List> result = new ArrayList <List> ();
        int remainder = list.size () % n; //(先計算出餘數)
        int number = list.size () / n; //然後是商
        int offset = 0;//偏移量
        for (int i = 0; i < n; i++) {
            List value = null;
            if (remainder > 0) {
                int start = i * number + offset;
                int end = (i + 1) * number + offset + 1;
                value = list.subList (start, end);
                remainder--;
                offset++;
            } else {
                int start1 = i * number + offset;
                int end1 = (i + 1) * number + offset;
                value = list.subList (start1, end1);
            }
            result.add (value);
        }
        return result;
    }