遍历集合的方法总结[Java]

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1. 遍历List方法：普通for循环

java

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

2. 遍历List方法：增强for循环

java

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

3. 遍历List方法：使用Iterator迭代器(一)

java

for(Iterator iter = list.iterator(); iter.hasNext(); ){
    String temp for(Iterator iter = list.iterator(); iter.hasNext(); ){
    String temp = (String)iter.next();
    System.out.println(temp);
}

4. 遍历List方法：使用迭代器(二)

java

Iterator iter = list.iterator();
while(iter.hasNext()){
    Object obj = iter.next();
    iter.remove();Iterator iter = list.iterator();
while(iter.hasNext()){
    Object obj = iter.next();
    iter.remove();//如果遍历时，删除集合中的元素，建议使用这种方式。
    System.out.println(obj);
}

5. 遍历Set方法：增强for循环

java

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

6. 遍历Set方法：使用Iterator迭代器

java

for(Iterator iter = set.iterator(); iter.hasNext(); ){
    String temp for(Iterator iter = set.iterator(); iter.hasNext(); ){
    String temp = (String)iter.next();
    System.out.println(temp);
}

7. 遍历Set方法：根据key获取value

java

Map<Integer, Man> maps = new HashMap<Integer, Man>();
Set<Integer> keyset = map.keyset();
Map<Integer, Man> maps = new HashMap<Integer, Man>();
Set<Integer> keyset = map.keyset();
for(Integer id : keyset){
    System.out.println(maps.get(id).name);
}

8. 遍历Map方法：根据key获取value

java

Map<Integer, Man> maps = new HashMap<Integer, Man>();
Set<Integer> keyset = map.keyset();
Map<Integer, Man> maps = new HashMap<Integer, Man>();
Set<Integer> keyset = map.keyset();
for(Integer id : keyset){
    Syetem.out.println(id);
}

9. 遍历Map方法：使用entrySet

java

Set<Entry<Integer, Man>> ss = maps.entrySet();
for(Integer iterator = ss.iterator(); iterator.hasNext(); ){
    Entry e = (Entry) iterator.next();
    System.out.println(e.getKey() + Set<Entry<Integer, Man>> ss = maps.entrySet();
for(Integer iterator = ss.iterator(); iterator.hasNext(); ){
    Entry e = (Entry) iterator.next();
    System.out.println(e.getKey() + "--" + e.getValue());
}