Access values of hashmap

Question

Possible Duplicate:
How do I iterate over each Entry in a Map?

I am having a MAP, Map<String, Records> map = new HashMap<String, Records> ();

public class Records 
{
    String countryName;
    long numberOfDays;

    public String getCountryName() {
        return countryName;
    }
    public void setCountryName(String countryName) {
        this.countryName = countryName;
    }
    public long getNumberOfDays() {
        return numberOfDays;
    }
    public void setNumberOfDays(long numberOfDays) {
        this.numberOfDays = numberOfDays;
    }

    public Records(long days,String cName)
    {
        numberOfDays=days;
        countryName=cName;
    }

    public Records()
    {
        this.countryName=countryName;
        this.numberOfDays=numberOfDays;
    }

I have implemented the methods for map, now please tell me How do I access all the values that are present in the hashmap. I need to show them on UI in android ?

What error you come across? You should able to get the record by the key you assigned for the record or you can iterate it by foreach loop. — Drogba, Oct 22 '12 at 08:50

score 6 · Answer 1 · edited Nov 24 '12 at 05:48

6

You can do it by using for loop

Set keys = map.keySet();   // It will return you all the keys in Map in the form of the Set


for (Iterator i = keys.iterator(); i.hasNext();) 
{

      String key = (String) i.next();

      Records value = (Records) map.get(key); // Here is an Individual Record in your HashMap
}

edited Nov 24 '12 at 05:48

Edward

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answered Oct 22 '12 at 09:25

M.Mohsin

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score 3 · Accepted Answer · edited May 23 '17 at 12:33

You can use Map#entrySet method, if you want to access the keys and values parallely from your HashMap: -

Map<String, Records> map = new HashMap<String, Records> ();

//Populate HashMap

for(Map.Entry<String, Record> entry: map.entrySet()) {
    System.out.println(entry.getKey() + " : " + entry.getValue());
}

Also, you can override toString method in your Record class, to get String Representation of your instances when you print them in for-each loop.

UPDATE: -

If you want to sort your Map on the basis of key in alphabetical order, you can convert your Map to TreeMap. It will automatically put entries sorted by keys: -

    Map<String, Integer> treeMap = new TreeMap<String, Integer>(map);

    for(Map.Entry<String, Integer> entry: treeMap.entrySet()) {
        System.out.println(entry.getKey() + " : " + entry.getValue());

    }

For more detailed explanation, see this post: - how to sort Map values by key in Java

Is there any way by which I can sort keys are per alphabetical order ? — , Oct 22 '12 at 09:02
@onkar. You can use `TreeMap` for that case. See this post: - http://stackoverflow.com/questions/922528/how-to-sort-map-values-by-key-in-java — Rohit Jain, Oct 22 '12 at 09:08

score 0 · Answer 3 · edited Aug 15 '19 at 14:43

0

map.values() gives you a Collection with all the values in your HashMap.

edited Aug 15 '19 at 14:43

Ihor Patsian

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answered Oct 22 '12 at 08:49

guido.rota

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4

score 0 · Answer 4 · edited Aug 15 '19 at 14:38

0

If you are having HashMap ready with data, then you just need to iterate over HashMap keys. Just implement an iteration and fetch data one by one.

Check this: Iterate through a HashMap

edited Aug 15 '19 at 14:38

Ihor Patsian

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answered Oct 22 '12 at 08:49

Paresh Mayani

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Access values of hashmap

4 Answers4