Return more than one value from a function in Java

Question

How to return more than one value from a function in Java? Can anyone give sample code for doing this using tuples? I am not able to understand the concept of tuples.

public class Tuple{
    public static void main(String []args){
        System.out.println(f());
    }
    static Pair<String,Integer> f(){
        return new Pair<String,Integer>("hi",3);
    }
    public class Pair<String,Integer> {
        public final String a;
        public final Integer b;

        public Pair(String a, Integer b) {
            this.a = a;
            this.b = b;
        }
    }
}

What is the mistake in the above code?

Java doesn't have tuples. If you like them, switch to Scala. — Rafe Kettler, Jan 21 '11 at 07:55
possible duplicate of [How to return multiple objects from a Java method?](http://stackoverflow.com/questions/457629/how-to-return-multiple-objects-from-a-java-method) — Joachim Sauer, Jan 21 '11 at 08:38
i always use HashMap for it. You can put whatever you want , keyed by your choice of names. its like a batch — kommradHomer, Jun 25 '12 at 09:30

score 4 · Answer 1 · answered Jan 21 '11 at 07:55

4

Create a class that holds multiple values you need. In your method, return an object that's an instance of that class. Voila!

This way, you still return one object. In Java, you cannot return more than one object, whatever that may be.

answered Jan 21 '11 at 07:55

darioo

46,442
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1

To be precise you return a _reference_ to an object. – Thorbjørn Ravn Andersen Jan 21 '11 at 08:05

score 2 · Answer 2 · edited Jan 12 '15 at 10:02

Is this what you are looking for?

public class Tuple {
    public static void main(String[] args) {
        System.out.println(f().a);
        System.out.println(f().b);
    }

    static Pair<String, Integer> f() {
        Tuple t = new Tuple();
        return t.new Pair<String, Integer>("hi", 3);

    }

    public class Pair<String, Integer> {
        public final String a;
        public final Integer b;

        public Pair(String a, Integer b) {
            this.a = a;
            this.b = b;
        }
    }
}

score 1 · Answer 3 · answered Jan 21 '11 at 07:55

1

You can't return more than one value.

You can return Array,Collection if it satisfies your purpose.

Note: It would be one value, reference to your Object[of array,collection] would be return.

answered Jan 21 '11 at 07:55

jmj

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438

score 1 · Answer 4 · answered Jan 21 '11 at 07:57

1

You can return an array from a java function:

   public static int[] ret() {
      int[] foo = {1,2,3,4};
      return  foo;
   }

answered Jan 21 '11 at 07:57

regality

6,496
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26

Still just one object (or reference to it...). The answer is 'no', but you can return an array, a collection, or a custom object encapsulating multiple objects. – Bart Kiers Jan 21 '11 at 09:58

score 1 · Answer 5 · answered Jan 21 '11 at 08:24

1

You can't return more than one value in java ( which is not python ). Write a method that just returns array or list or any other object like this

answered Jan 21 '11 at 08:24

score 0 · Answer 6 · answered Jul 05 '16 at 13:37

What if what you are returning are of different data types just like your situation. Or for example, Lets say you are returning a String name and an integer age. You can you JSON from the org.json library. You can get the jar at http://www.java2s.com/Code/Jar/j/Downloadjavajsonjar.htm

public JSONObject info(){
     String name = "Emil";
     int age = 25;
     String jsonString  ="{\"name\":\""+ name+"\",\"age\":"+ age +"}";
     JSONObject json = new JSONObject(jsonString);
     return json ;
}

Afterwards, if you want to get the data somewhere in your program, this is what you do:

//objectInstanceName is the name of the instantiated class
JSONObject jso = objectInstanceName.info();
String name = jso.getString("name");
int age = jso.getInt("age");
System.out.println(name + " is "+ age + " years old");

//Output will be like
Emil is 25 years old

Hope you try it. Or you can read more on JSON in java if you HAVEN'T.

Return more than one value from a function in Java

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