[英]java Hashmap : Get the key with maximum number of values
I am trying to get the key with maximum number of values (not max value). 我正在尝试获取具有最大数量的值(而不是最大值)的钥匙。 I ave tried a couple of thing like counting values iterating over each key. 我尝试了几件事,例如计算对每个键进行迭代的值。 But they boil down to problem finding a key from value which is problematic when we have same values. 但是他们归结为从价值中寻找钥匙的问题,当我们拥有相同的价值时,这是有问题的。
// calculate the length
for(String key : map.keySet())
{
len.add(map.get(key).size());
}
// sort the length
Collections.sort(len, Collections.reverseOrder() );
If you're using Java 8, this could just be 如果您使用的是Java 8,则可能只是
String maxKey = map.entrySet().stream()
.max(Comparator.comparingInt(entry -> entry.getValue().size()))
.get().getKey();
if not, I'd tend to write this as 如果没有,我倾向于写成
String maxKey = Collections.max(map.entrySet(),
new Comparator<Map.Entry<String, List<Value>>>() {
@Override public int compare(
Map.Entry<String, List<Value>> e1, Map.Entry<String, List<Value>> e2) {
return Integer.compare(e1.getValue().size(), e2.getValue().size());
}
}).getKey();
...or, you could just write ...或者,你可以写
String maxKey = null;
int maxCount = 0;
for (Map.Entry<String, List<Value>> entry : map.entrySet()) {
if (entry.getValue().size() > maxCount) {
maxKey = entry.getKey();
maxCount = entry.getValue().size();
}
}
return maxKey;
String maxKey = null;
for (String key : map.keySet())
{
if (maxKey == null || map.get(key).size() > map.get(maxKey).size())
{
maxKey = key;
}
}
This would be my solution to the problem. 这将是我解决问题的方法。 After execution, maxKey
is key with the most values. 执行后, maxKey
是具有最多值的键。
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