CODEWITHSUNDEEP
javavectorhashmap
Malcon Rhymes
Malcon Rhymes

Reputation: 1

Working with a vector of maps in Java

I'd like to have a vector which contains some (possibly many) Hashmaps of which have a string as the key and an integer as the value. How could I check whether my vector of Hashmaps already contains a certain key, and if so, increment the corresponding key's value by 1?

What I am trying to accomplish is to count the number of times a word occurs in a document. My thinking was that I could use a HashMap to store the number of times a word occurs. But I want to check if my vector already contains a map with a given word before adding a new map to my vector. If my vector DOES contain a map with the given word, increment the value field (in this case numOfTimesOccurredSoFar).

Is this possible?

Upvotes: 0

Views: 3317

Answers (2)

Ray Tayek
Ray Tayek

Reputation: 10003

import java.util.Map;
import java.util.TreeMap;
public class So13315440 {
    void add(String word) {
        if(map.containsKey(word))
            map.put(word,map.get(word)+1);
        else map.put(word,1);
    }
    void run() {
        add("foo");
        add("foo");
        add("bar");
        System.out.println(map);
    }
    public static void main(String[] args) {
        new So13315440().run();
    }
    Map<String,Integer> map=new TreeMap<String,Integer>();
}

Upvotes: 0

Z Reeder
Z Reeder

Reputation: 21

Unless I misunderstand what you want to do, I see no reason to store maps in a vector when you can use a single map to map words to word count. For each word, check if the map has that word as a key, and if it does, add 1 to the value mapped to the word. If the word isn't in the map yet, add a new key-value pair.

Upvotes: 2

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