Get values of a HASHMAP

Question

I'm trying to access to the values of a pair from a hashmap. I have got a Map where Integer is the key and info is the value. I want to iterate through the map and get the specific data field (namePlayer) from the info object.

class info{
    public String namePlayer;
    public String knowledge; 
    public int coins;

    info(String nom,String coneixament,int monedes){
        namePlayer=nom;
        knowledge=coneixament;
        coins=monedes;
    }

    void setMonedes(int monedes){
        coins=monedes;
    }

    void setConeixement(String confianza){
        knowledge=confianza;
    }
    String getConeixament(){
        return knowledge;
    }
    String getNames(){
        return name;
    }
}
public class Memory{
    private Map<Integer,info> k;

    Memory(){
        k= new HashMap<Integer, info>();
    }

    void getValues(){
        Iterator it = _infoPartida.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry pair = (Map.Entry)it.next();
            info s = pair.getValues();// error
            String name = s.getNames():
         }
    }
}

What is the actual question? getValues() is of type void, so it won't return anything? — JohannisK, May 19 '16 at 09:05
First of all, it's `getValue()`, not `getValues()`. Second of all, `getValue()` will return you an `Object`, since you are using raw types. — Eran, May 19 '16 at 09:06
An entry contains a key and a value, use `pair.getValue()` to get its value. — Arnaud, May 19 '16 at 09:06
I want to print ONLY the name of the player that has the key 2 for example . — bb88, May 19 '16 at 09:07
Then you don't need to iterate over the entire collection. You can .get(7) the value from the HashMap. — JohannisK, May 19 '16 at 09:09

score 0 · Answer 1 · answered May 19 '16 at 09:09

You need to add the generics info to your Iterator

void getValues(){
    Iterator<info> it = k.entrySet().iterator();
    while (it.hasNext()) {
        Map.Entry pair = it.next();
        info s = pair.getValue();
        String name = s.getNames():
    }
}

Rainer · Answer 2 · 2016-05-19T09:18:54.223

0

class names are upper case in Java (Info - not info)
k is an horrible name for a variable

This is very easy in Java

for (Info info : k.values()){
    System.out.println(info.getNames();
}

There you go.

For more information how to handle maps please have a look at the dokumentation

edited May 19 '16 at 09:18

answered May 19 '16 at 09:12

Rainer

761
5
20

btw. Not sure if "in" or ":" is correct... doing a lot of python in the past ;-) – Rainer May 19 '16 at 09:14

score 0 · Answer 3 · answered May 19 '16 at 09:16

0

void getValues(){
    Iterator it = _infoPartida.entrySet().iterator();
    while (it.hasNext()) {
        Map.Entry pair = (Map.Entry)it.next();
        info s = pair.getValues();// error
        String name = s.getNames():
     }
}

should be something like

public String getPlayerName(int index) {
   info i = k.get(index);
   return i.getNames();
}

answered May 19 '16 at 09:16

JohannisK

535
2
10

Also, look at the comments and change your syntax... Classes should start with upper names, variable names should describe what they are containing. – JohannisK May 19 '16 at 09:22

score 0 · Answer 4 · answered May 19 '16 at 09:17

0

As Mr. @Lee pointed out.. you have to add generics to your Iterator...
and Map.Entry

void getValues(){
    Iterator<Map.Entry<Integer,info>> it = _infoPartida.entrySet().iterator();
    while (it.hasNext()) {
        Map.Entry<Integer,info> pair = it.next();
        info s = pair.getValue();
        String name = s.getNames();
     }
}

Assuming that k is _infoPartida.
Also, consider @Rainer's 3 points.

answered May 19 '16 at 09:17

Pradhan

518
4
14

@JohannisK, You are right. It just corrects the `getValues` method. This was posted before he updated his actual requirements. – Pradhan May 20 '16 at 01:45

score 0 · Answer 5 · answered May 19 '16 at 09:50

0

You have two options here. Either loop through using a for loop or an iterator. For loop is easy as shown by @Rainer however Iterator is more powerful because it allows you to remove the element you are one and has more functionality.

answered May 19 '16 at 09:50

Julian

781
1
11
32

Get values of a HASHMAP

5 Answers5