/**
* Map排序與遍歷
* Map 和 List 都是先進先出
*
* */
public static void main(String[] args){
Map<Integer, Integer> map = new HashMap<Integer, Integer>();
map.put(1, 1);
map.put(2, 2);
map.put(3, 3);
map.put(4, 4);
map.put(5, 5);
// map.
List<Integer> list = new ArrayList<Integer>();
list.add(1);
list.add(2);
list.add(3);
list.add(4);
// int i = 0;
for(int i = 0; i < list.size(); i++){
System.out.println( list.get(i)+ "-----" + i);
// list.remove(i);
// i++;
}
System.out.println("通過Map.entrySet遍歷key和value");
for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}
}
====================================================================================================
遍歷map的四種方法:
public static void main(String[] args) {
Map<String, String> map = new HashMap<String, String>();
map.put("1", "value1");
map.put("2", "value2");
map.put("3", "value3");
//第一種:普遍使用,二次取值
System.out.println("通過Map.keySet遍歷key和value:");
for (String key : map.keySet()) {
System.out.println("key= "+ key + " and value= " + map.get(key));
}
//第二種
System.out.println("通過Map.entrySet使用iterator遍歷key和value:");
Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
while (it.hasNext()) {
Map.Entry<String, String> entry = it.next();
System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}
//第三種:推薦,尤其是容量大時
System.out.println("通過Map.entrySet遍歷key和value");
for (Map.Entry<String, String> entry : map.entrySet()) {
System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}
//第四種
System.out.println("通過Map.values()遍歷所有的value,但不能遍歷key");
for (String v : map.values()) {
System.out.println("value= " + v);
}
}