ArrayList: deletes elements and arraylist elements.

ArrayList: deletes elements and arraylist elements.
 

1. Use a for loop (only progressive traversal is allowed)

    public static void main(String[] args) {        List<String> list = new ArrayList<String>();        list.add("111");        list.add("222");        list.add("333");        list.add("222");        list.add("444");        for (int i = list.size() - 1; i >= 0; i--)        {            if ("222".equals((String)list.get(i)))            {                list.remove(i);                System.out.println(list.get(i));            }        }        System.out.println("=========" + list.size());        for (String str : list)        {            System.out.println(str);        }    }

Running result:

222
222
=========== 3
111
333
444

 

2. Use the iterator to delete elements:

    public static void main(String[] args) {        List<String> list = new ArrayList<String>();        list.add("111");        list.add("222");        list.add("333");        list.add("222");        list.add("444");        Iterator<String> itr = list.iterator();        while (itr.hasNext())        {            String str = itr.next();            if ("333".equals(str))            {                itr.remove();            }        }        for (String str : list)        {            System.out.println(str);        }            }

Running result:

111
222
222
444

 

 

E	remove(int index)  Removes the element at the specified position from the list.
boolean	remove(Object o)  Remove the specified Element (if any) that appears for the first time from the list ).

List. remove (2 );

List. remove ("222 ");

Both methods can be used independently, instead of being used only during the time period.