遍历List、Map删除元素

遍历List删除元素

方法一：

List<String> list = new ArrayList<>();
list.add("1");
list.add("2");
list.add("3");
list.add(null);
list.add("5");

for(int i=0; i<list.size(); i++){
    list.remove(i);
    i--;
}
System.out.println(list.size());

方法二：

List<String> list = new ArrayList<>();
list.add("1");
list.add("2");
list.add("3");
list.add(null);
list.add("5");
for (Iterator iterator = list.iterator(); iterator.hasNext();) {
    String tmp = (String)iterator.next();
    iterator.remove();
}
System.out.println(list.size());

遍历Map删除元素

方法一：

Map<String,String> map = new HashMap<>();
map.put("1","aaa");
map.put("2","bbb");
map.put("3","ccc");
map.put("4","ddd");
map.put("5","eee");

Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
while (it.hasNext()) {
    Map.Entry<String, String> entry = it.next();
    it.remove();
}
System.out.println(map.size());

方法二：

Map<String,String> map = new HashMap<>();
map.put("1","aaa");
map.put("2","bbb");
map.put("3","ccc");
map.put("4","ddd");
map.put("5","eee");

for (Iterator<Map.Entry<String, String>> it = map.entrySet().iterator(); it.hasNext();) {
    Map.Entry<String, String> entry = it.next();
    it.remove();
}
System.out.println(map.size());