Java associative-array

Question

Java doesn't support associative arrays, however this could easily be achieved using a Map. E.g.,

Map<String, String> map = new HashMap<String, String>();
map.put("name", "demo");
map.put("fname", "fdemo");
// etc

map.get("name"); // returns "demo"

Even more accurate to your example (since you can replace String with any object that meet your needs) would be to declare:

List<Map<String, String>> data = new ArrayList<>();
data.add(0, map);
data.get(0).get("name"); 

See the official documentation for more information

Java doesn't have associative arrays like PHP does.

There are various solutions for what you are doing, such as using a Map, but it depends on how you want to look up the information. You can easily write a class that holds all your information and store instances of them in an ArrayList.

public class Foo{
    public String name, fname;

    public Foo(String name, String fname){
        this.name = name;
        this.fname = fname;
    }
}

And then...

List<Foo> foos = new ArrayList<Foo>();
foos.add(new Foo("demo","fdemo"));
foos.add(new Foo("test","fname"));

So you can access them like...

foos.get(0).name;
=> "demo"

You can accomplish this via Maps. Something like

Map<String, String>[] arr = new HashMap<String, String>[2]();
arr[0].put("name", "demo");

But as you start using Java I am sure you will find that if you create a class/model that represents your data will be your best options. I would do

class Person{
String name;
String fname;
}
List<Person> people = new ArrayList<Person>();
Person p = new Person();
p.name = "demo";
p.fname = "fdemo";
people.add(p);

Look at the Map interface, and at the concrete class HashMap.

To create a Map:

Map<String, String> assoc = new HashMap<String, String>();

To add a key-value pair:

assoc.put("name", "demo");

To retrieve the value associated with a key:

assoc.get("name")

And sure, you may create an array of Maps, as it seems to be what you want:

Map<String, String>[] assoc = ...

There is no such thing as associative array in Java. Its closest relative is a Map, which is strongly typed, however has less elegant syntax/API.

This is the closest you can get based on your example:

Map<Integer, Map<String, String>> arr = 
    org.apache.commons.collections.map.LazyMap.decorate(
         new HashMap(), new InstantiateFactory(HashMap.class));

//$arr[0]['name'] = 'demo';
arr.get(0).put("name", "demo");

System.out.println(arr.get(0).get("name"));
System.out.println(arr.get(1).get("name"));    //yields null