Question

I am trying to code a frequency analysis program for fun. I currently have everything being stored in a hashmap and I index the values using an iterator.

My values however are stored as integers, how could I go about converting these entries into percentages, or a more accessible format so i can compare them later?

I was thinking i could use getValue(), but this is an object.

Can anyone point me in the right direction? Should i be using a hashmap? should i transfer them into an array the size of the hashmap?

Answer 1

Hashmaps are indeed ideal for building freuqency tables, and the value type should definitely be Integer (if you try to store percentages, you’d have to update all percentages each time you add a new value). If you have another class that contains the hashmap as a field, you could make a method for retrieving the percentage of a specific character (note that I don’t recall the exact method names):

public float getPercentage(char c) {
    if (!map.containsKey(c))
        return 0;
    int sum = 0;
    for (Integer count : map.values())
        sum += count;
    return map.get(c) / (float)sum;
}

If you want the percentages for all characters, you should make a method that produces a new hashmap that contains the percentages, calculated in a similar fashion. If you want to be fancy (read: overengineer), you could even implement an Iterator that produces percentages from the original Integer hashmap.