Question

我有以下类型ArrayList<List<String>>

Array_AcidExp[[Statistics (pH), Upright, Recumbent, Total], [Upright, Normal, Recumbent, Normal, Total, Normal], [Clearance pH  :  Channel 7], [Minimum, 4.69, , 2.42], [Maximum, 7.88, , 7.51, , 7.88], [Mean, 6.33, , 6.41, , 6.37], [Median, 6.62, , 6.40, , 6.49]]

我试过以下没有运气：

 for (int i = 0; i < Arr_AcidExp_pattern_table2d.size(); i++) {
Arr_AcidExp_pattern_table2d.removeAll(Collections.singleton(null));
Arr_AcidExp_pattern_table2d.get(i).removeAll(Collections.singleton(" "));
             }

我该怎样做才能摆脱空元素？

Answer 1

这将删除所有内部空值

 for (List<String> internal : Array_AcidExp) {
        if (internal != null) {
            for (int i = 0; i < internal.size(); i++) {
                if (internal.get(i) == null) {
                    internal.remove(i)
                }
            }
        }
    }

没有运行它......

Answer 2

你也可以在java8中使用removeIf()

 public static void main(String[] args) {
    ArrayList<String> list = new ArrayList<String>();
    list.add("yo");
    list.add(null);
    list.add(" ");
    System.out.println(list);
    list.removeIf(new Predicate<String>() {
        @Override
        public boolean test(String t) {
            // removes all the elements from the list, for which the
            // following condition returns true
            return t == null || t.equals(" ");
        }
    });
    System.out.println(list);
 }

如何摆脱二维arrayList中内部arrayList的null元素

2 个答案: