Question

I was wondering if it is possible to compare items in multiple hashMaps to each other:

HashMap<String,String> valueMap = new HashMap<String, String>();
HashMap<String,Integer> formulaMap = new HashMap<String, Integer>();

What I would basically like to do is something like:

if(the second string in valueMap is the same as the first string in formulaMap){
}

Is there a short way to achieve this or do I have to compare the strings before they are included into the hashMaps. My Integer at this stage of the program is required to take a null value. I can achieve my goals with a multi-dimensional array, but a solution like this would be more elegant and less time consuming.

Answer 1

By using a LinkedHashMap you can have a map that respects the insertion order of different values. Everything you have to do is iterate over the entrySet of the map until you reach the position you’re looking for.

Plus: If you also need ordering, you can have a look at the TreeMap which inserts elements in order based on a criteria defined by you (You can pass a Comparator as a parameter for the map).

This order will apply to the keys of the map tough, so if you need value ordering you’re going to have to come up with a little more complex solution (as in sorting the entry set directly and adding the values to another map, for example).