Returning more than one elements from a function

Question

I have a function in Java, but I'm trying to return 3 elements from a function, but so far no luck.

public String retrieveStudentInfo() {
    String name = "Miley";
    String grade = "56"
    String ID = "1043"
    return name,grade,ID; //trying to return all the elements in this function.
}

based on the function above, I'm trying to return the name,grade and ID at the same time, through a variable like below:

String getStudentInfo = this.retrieveStudentInfo();

Could anyone please help me on this. I've specified the return data type as String but it wouldn't let me return them.

A method can only return one item at a time. That item can be an object, though. — RealSkeptic, Apr 28 '19 at 09:42

score 3 · Answer 1 · edited Apr 28 '19 at 09:43

3

You should wrap this properties in some class and then return instead of String the object of class like StudentInfo

public class StudentInfo {
    String name;
    String grade;
    String ID;
}

edited Apr 28 '19 at 09:43

John Kugelman

349,597
67
533
578

answered Apr 28 '19 at 09:42

Piotr S

137
3

score 2 · Answer 2 · answered Apr 28 '19 at 09:43

It doesn't work because you can't return tuples in java. You can do like this:

Declare a class, StudentInfo, which contains 3 attributes of type String - name, grade & ID.
Define the return value of retrieveStudentInfo to be StudentInfo.
Create an instance of it in the last line of the retrieveStudentInfo and return it.

score 1 · Answer 3 · answered Apr 28 '19 at 09:42

1

public String[] retrieveStudentInfo() {
    String name = "Miley";
    String grade = "56"
    String ID = "1043"
    String[] data = new String[] {name ,grade ,ID};
    return data;
}

answered Apr 28 '19 at 09:42

Alon Adler

3,984
4
32
44

2

This is a bad idea, because in the real world, `grade` would be an `int`, and then you can't use a `String` array. You'll either have to generalize to `Object[]` with boxing and casting, or use a better solution. – RealSkeptic Apr 28 '19 at 09:44
1

@RealSkeptic I understand and totally agree with what you say. But, my intention here is giving a basic answer to a basic question. – Alon Adler Apr 28 '19 at 09:46

score 1 · Answer 4 · answered Apr 28 '19 at 10:02

1

If you want to return this object as String you can do something like this: return name + “ “ + grade + “ “ + ID;

It will be complicated however to interpret this String. So better is to return the complete Object.

answered Apr 28 '19 at 10:02

Axel Podehl

4,034
29
41

score 0 · Answer 5 · answered Apr 28 '19 at 09:45

You could create an object called AnswerObject:

Define this object to have 3 public properties of String:

public class AnswerObject {
public String Name;
public String Grade;
public String ID;
}

Return this object from your method and you will have an answer with 3 elements.

score 0 · Answer 6 · answered Apr 28 '19 at 13:15

User Tuple from vavr

private static Tuple3<Integer, String, Object> returnThreeElements() {
    return Tuple.of(1, "HelloWorld", new Object());
}

get element from Tuple can use method like the follow code:

public static void main(String[] args) {
    Tuple3<Integer, String, Object> result = returnThreeElements();
    System.out.println(result._1());
    System.out.println(result._2());
    System.out.println(result._3());
}

Returning more than one elements from a function

6 Answers6