How to retrive Value by using key from Hashmap<String, String>?

Question

Here is my code:

public static HashMap<String, ArrayList<String>> CountryMap = new HashMap<String, ArrayList<String>>();

ArrayList<String> stateInd = new ArrayList<String>();
ArrayList<String> stateUSA = new ArrayList<String>();
stateInd.add("GJ");
stateInd.add("MP");
stateUSA.add("NJ");
stateUSA.add("NY");

CountryMap.put("India",stateInd);            
CountryMap.put("USA",stateUSA);

for(int i=0;i<CountryMap.size();i++){
    for (Entry<String, ArrayList<String>> entry : CountryMap.entrySet()) {
        if (entry.getKey().equals("India") {
            ArrayList<String> result = new ArrayList<String>();             
            # how to add Value of CountryMap with "India" as a Key to result ArrayList??
        }
    }
}

I want to add values to another ArrayList from hashmap which have "India" as key ?

I tried..

result.add(CountryMap.get("India"));

But it didn't worked. It add all values.

Why are you iterating using for loop? ArrayList<String> indiaList = CountryMap.get("India"); — Sandeep Nair
– Sandeep Nair, Commented Jun 28, 2012 at 11:44

Alpesh Prajapati · Accepted Answer · 2012-06-28 12:01:16Z

1

solutions 1:

    result.addAll(CountryMap.get("India"));

solutions 2:

    result.add(CountryMap.get("India").toString());

Do try to have a look at all functions and exceptions raised. Reply if it works

answered Jun 28, 2012 at 12:01

Alpesh Prajapati

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Comments

Fathah Rehman P · Accepted Answer · 2012-06-29 06:59:05Z

public class NewClass4{
 public static HashMap<String, ArrayList<String>> CountryMap = new HashMap<String, ArrayList<String>>();
    public static void main(String[] args)
    {
        ArrayList<String> stateInd = new ArrayList<String>();
        ArrayList<String> stateUSA = new ArrayList<String>();
        stateInd.add("GJ");
        stateInd.add("MP");
        stateUSA.add("NJ");
        stateUSA.add("NY");

        CountryMap.put("India",stateInd);            
        CountryMap.put("USA",stateUSA);

        ArrayList<String> result = new ArrayList<String>();
        result=CountryMap.get("India");
        if(result!=null){
            // means CountryMap contain key "India"
        }
    }
}

dimas · Accepted Answer · 2012-07-29 17:17:51Z

Hi I know this is almost a month old but couldn't resist to give my thoughts to it. The solution is quite simple if I got your question right.

public static void main(String[] args) {
        HashMap<String, ArrayList<String>> CountryMap = new HashMap<String, ArrayList<String>>();

        ArrayList<String> stateInd = new ArrayList<String>();
        ArrayList<String> stateUSA = new ArrayList<String>();
        ArrayList<String> result = new ArrayList<String>();
        stateInd.add("GJ");
        stateInd.add("MP");
        stateUSA.add("NJ");
        stateUSA.add("NY");

        CountryMap.put("India",stateInd);            
        CountryMap.put("USA",stateUSA);


        for (String key: CountryMap.keySet()){

            if (key.equals("India")){
                result.add(key);
            }
        }

        for (String country: result){
            System.out.print("\n"+country+" ");
        }
}

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