how to get hashmap content of arraylist in java?

Question

I am using the following code to save hashmap content into arraylist.

HashMap jediSaber = new HashMap();  
ArrayList<HashMap> valuesList = new ArrayList();

for(int i = 0; i< 4;i++) {
    jediSaber.put("white","white_name"+i);  
    jediSaber.put("blue","blue_name"+i);   
    valuesList.add(i, jediSaber);           
    System.out.println("list ontent:"+i+":"+valuesList.get(i).values());
}

    `

output is as follows:

              list content:0:[blue_name0, white_name0]
              list content:1:[blue_name1, white_name1]
              list content:2:[blue_name2, white_name2]
              list content:3:[blue_name3, white_name3]

When i try to display the content of arraylist in outside with the following code,

System.out.println("list content:");
for(int i = 0;i<valuesList.size();i++){ 
    System.out.println("list:"+i+":"+valuesList.get(i).values());
}

It is showing the following output,

             list content:0:[blue_name3, white_name3]
             list content:1:[blue_name3, white_name3]
             list content:2:[blue_name3, white_name3]
             list content:3:[blue_name3, white_name3]

My problem is i need to display the content of arraylist of hashmap.

I think something i missed in second part. Can anybody help me to solve this minor issue?

Thanks in advance!!..

hmjd · Accepted Answer · 2012-10-03 08:53:33Z

1

This is adding the same HashMap each time to the ArrayList:

valuesList.add(i, jediSaber);

Create a new HashMap each time within the for and add it:

List<HashMap<String, String>> valuesList =
    new ArrayList<HashMap<String, String>>();

for (int i = 0; i < 4; i++)
{
    HashMap<String, String> m = new HashMap<String, String>();
    m.put("white", "white_name" + i);
    m.put("blue",  "blue_name"  + i);
    valuesList.add(m);
}

System.out.println(valuesList.toString());

edited Oct 3, 2012 at 8:53

answered Oct 3, 2012 at 8:38

hmjd

122k21 gold badges216 silver badges259 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

shiva Over a year ago

Thanks for your reponse. Its working fine. have created hasmap within forloop and added into arraylist.

Subhrajyoti Majumder · Accepted Answer · 2012-10-03 08:48:37Z

0

        List<Map> valuesList = new ArrayList();
        for (int i = 0; i < 4; i++) {
            Map<Object, Object> jediSaber = new HashMap<>();
            jediSaber.put("white", "white_name" + i);
            jediSaber.put("blue", "blue_name" + i);
            valuesList.add(jediSaber);
            Set<Entry<Object, Object>> entrySet = jediSaber.entrySet();
            for (Entry<Object, Object> entry : entrySet) {
                System.out.println(entry.getKey() + "-" + entry.getValue());
            }
        }

answered Oct 3, 2012 at 8:48

Subhrajyoti Majumder

41.3k13 gold badges84 silver badges103 bronze badges

Comments

David Grant · Accepted Answer · 2012-10-03 08:48:49Z

0

Try pulling jediSaber inside your for loop, like so:

for(int i = 0; i < 4; i++) {
    Map<String, String> jediSaber = new HashMap<String, String>();

You should also parameterize valuesList too:

List<Map<String, String>> valuesList = new ArrayList<Map<String, String>>();

P.S. There's no need to call add(i, jediSaber) with the index argument: valuesList.add(jediSaber) will have the same effect.

edited Oct 3, 2012 at 8:48

answered Oct 3, 2012 at 8:43

David Grant

14.4k3 gold badges62 silver badges65 bronze badges

Collectives™ on Stack Overflow

how to get hashmap content of arraylist in java?

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related