如何遍历TreeMap?
可能重复:
如何迭代Map中的每个条目?
我想迭代一个TreeMap
,对于所有具有特定值的键,我希望它们被添加到一个新的TreeMap
。 我怎样才能做到这一点?
假设类型为TreeMap <String,Integer>:
for(Map.Entry<String,Integer> entry : treeMap.entrySet()) {
String key = entry.getKey();
Integer value = entry.getValue();
System.out.println(key + " => " + value);
}
(键和值类型可以是任何类的课程)
//create TreeMap instance
TreeMap treeMap = new TreeMap();
//add key value pairs to TreeMap
treeMap.put("1","One");
treeMap.put("2","Two");
treeMap.put("3","Three");
/*
get Collection of values contained in TreeMap using
Collection values()
*/
Collection c = treeMap.values();
//obtain an Iterator for Collection
Iterator itr = c.iterator();
//iterate through TreeMap values iterator
while(itr.hasNext())
System.out.println(itr.next());
要么:
for (Map.Entry<K,V> entry : treeMap.entrySet()) {
V value = entry.getValue();
K key = entry.getKey();
}
要么:
// Use iterator to display the keys and associated values
System.out.println("Map Values Before: ");
Set keys = map.keySet();
for (Iterator i = keys.iterator(); i.hasNext();) {
Integer key = (Integer) i.next();
String value = (String) map.get(key);
System.out.println(key + " = " + value);
}
只是指出遍历任何映射的通用方法:
private <K, V> void iterateOverMap(Map<K, V> map) {
for (Map.Entry<K, V> entry : map.entrySet()) {
System.out.println("key ->" + entry.getKey() + ", value->" + entry.getValue());
}
}
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