Question

I am translating a Javascript function to Java, and I am having troubles with this text variable below, how to declare and use it in Java:

Javascript:

var text={}; // Index will be several arrays, and value an integer
var word; // Will contain several chars, like a string
var myChar; // Will contain only one char
var value; // Will contain one integer
[...]
if(text[word+myChar]!=null)
{ // In this comparison, word is "hell", myChar is "o" and value is 1234
  text[word+myChar]=value; 
}

Thanks for your help

Answer 1

It would be very helpful if we can see what you have tried so far (in Java). This can help us put into context better what you’re trying to accomplish.

Here are my tips from what I can gather:

1. It appears you’re creating a mapping of strings -> integers (or something like that). This would be clearly represented by a HashMap<K,V> in Java. This will say “Map an instance of a value of type V to a key of type K” where K and V can be decided by you. With this, you could create an instance of a HashMap<String, Integer> where you could get/set integer values within the hash map at particular string key.
2. You could use string concatenation (I assume that’s the operation occurring when you use word + myChar in JS) in a similar manner in Java. You would form a single String object from this.
3. With a HashMap, you may want to use containsKey(K key) or get(K key) depending on whether you want to see if the key exists in the map at all, or if the value at that key in the map is non-null. This will depend on the context of the problem and what you want to accomplish.

Here’s a quick (not tested) example of what it may look like:

import java.util.*;

public class WordIntMap {
    public static void main(String[] args) {
        HashMap<String, Integer> text = new HashMap<String, Integer>();
        String word = "hell";
        char myChar = 'o';
        int value = 1234;

        String key = word + myChar;

        if (text.get(key) != null) {
            text.put(key, value);
        }
    }
}