六种集合的遍历方式总结（List Set Map Queue Deque Stack)

List

方式一：for循环

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

方式二：for each循环遍历

for(String s : list){
    System.out.println(s);
}

方式三：iterator迭代器遍历

Iterator<String> it = list.iterator();
while(it.hasNext()){
      System.out.println(it.next());
}
      

Set

方式一：for each

for(String s : set){
    System.out.println(s);
}

方式二：iterator迭代器遍历

Iterator it = set.iterator();
while(it.hasNext()){
      System.out.println(it.next());
}

Map

方式一：for each 遍历Map的key值

for(String key : map.keySet()){
   Integer value = map.get(key);
   System.out.println(key + "=' =value);
}

方式二：for each 同时遍历key和value

for(Map.Entry<String,Integer> entry : map.entrySet()){
   String key = entry.getKey();
   Integer value = entry.getValue();
   System.out.println(key + "=" + value):
}

Queue队列（FIFO)

方式一: for each 遍历队列

for(String s : queue){
   System.out.println(s);
}

方式二：iterator 迭代器遍历队列

String item = null;
while((item = queue.poll()) != null){
     System.out.println(item);
}

Deque双端队列

iterator迭代器遍历

String item = null;
while((item = deque.poll.set()) != null){
     System.out.println(item);
}

Stack栈(LIFO)

while(!stack.isEmpty()){
     System.out.println(stack.poll());
}