HashMap的遍历方法
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通过keyset
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通过 Map.entrySet().iterator()
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通过foreach ---- Map.entryset, 当hashmap很大时,推荐使用这种方式。
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通过Valueset
public static void main(String[] args) {
HashMap<Integer, String> hashmap = new HashMap<>();
hashmap.put(1,"gogo");
hashmap.put(2,"wade");
hashmap.put(3,"james");
hashmap.put(4,"curry");
// 1. 通过Map.keySet遍历key和value:
for (int key : hashmap.keySet()){
System.out.println("key: "+ key + "; value: " + hashmap.get(key));
}
//2. 通过Map.entrySet使用iterator遍历key和value:
Iterator<Map.Entry<Integer, String>> it = hashmap.entrySet().iterator();
while (it.hasNext()){
Map.Entry<Integer, String> entry = it.next();
System.out.println("key: "+ entry.getKey() + "; value: " + entry.getValue());
}
//3. 通过Map.entrySet遍历key和value
for(Map.Entry<Integer, String> entry : hashmap.entrySet()){
System.out.println("key: "+ entry.getKey() + "; value: " + entry.getValue());
}
//4. 通过Map.values()遍历所有的value,但不能遍历key
for (String value : hashmap.values()) {
System.out.println("value: "+value);
}
}
转载自:https://blog.csdn.net/u012156116/article/details/80597284
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