Java: Creating a 2D ArrayList to store an integer and string?

Question

I need to store 2 arrays of values that are connected to each other. The arrays consists of a set of strings and a set of integer/double values. The size of the data are not fixed.

An example:

Data 1: AA, 13    
Data 2: BB, 6    
Data 3: GG, 2

I am trying to look at 2D Arrays. Is there a better way to store the values? There's a possibilities that I might need multidimensional arrays to store the values as well. Can anyone point me in the right direction or show me a way to create the 2D arrays and how to add/retrieve the elements?

Do you need to differentiate between ints and doubles? Or can it be all pairs of String,Double ? — Borgleader
– Borgleader, Commented Sep 13, 2012 at 2:38
It's either pairs of String-double or String-integers. Sorry for the confusion. — Cryssie
– Cryssie, Commented Sep 13, 2012 at 2:51

Makoto · Accepted Answer · 2012-09-13 02:38:03Z

7

It would be far better to use a Map. Maps have key-value pairs, so you could naturally store Strings and Integers in this manner.

Map<String, Integer> myMap = new HashMap<String, Integer>();

answered Sep 13, 2012 at 2:38

Makoto

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6 Comments

zw324 Over a year ago

Map has two type parameters, set only has one.

Makoto Over a year ago

Ah, that's right. I must've been working with something else for far too long.

Cryssie Over a year ago

Hi Makoto, is it possible to use Map to store a set of 3 values like String-integer-integer (AA, 3, 6) or String-integer-double(KK, 6, 2.5)?

Makoto Over a year ago

Yes - instead of storing a single Integer object, you would store a List<Integer>.

Cryssie Over a year ago

Unfortunately Makoto, Map only allows unique keys and I'm afraid my data might contain same values. It's a great learning experience nevertheless.

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TaherT · Accepted Answer · 2012-09-13 09:08:10Z

1

You can also use like this there are two ways if you want only ArrayList as a datastructure create a class like this :

    public Class Data{
    private String myString;
    private Integer myInteger;
    public String getMyString() {
        return myString;
    }

    public void setMyString(String myString) {
        this.myString = myString;
    }

    public Integer getMyInteger() {
        return myInteger;
    }

    public void setMyInteger(Integer myInteger) {
        this.myInteger = myInteger;
    }
}
List<Data> list = new ArrayList<Data>();

or else you can use like this

List<Object[]> list = new ArrayList<Object[]>();

answered Sep 13, 2012 at 9:08

TaherT

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