Question

I have a hashmap, I wish to get an array of the values in this hashmap, but I wish for the array to be sorted by the keys in the hashmap.

For instance if the map looks like this:

• <2,obj1>
• <4,obj2>
• <0,obj3>
• <10,obj4>
• <5,obj5>
• <1,obj6>
• <15,obj7>
• <3,obj8>

I want the array to be: [obj3,obj6,obj1,obj8,obj2,obj5,obj4,obj7]

The faster the better. Is there a built in way to do this?

Answer 1

Sounds like you want a SortedMap, specifically a TreeMap. You can use the fact that the map maintains a sorted list of keys to generate your output array, e.g. by using SortedMap.values() or by iterating over the entries in the map.