Thread: trying to create an array with multiple values per instance

That bit of code there is not valid Java. What you want is a two-dimensional array.

Java Code:

Object[][] foo = new Object[] {
    new Object[] {"Boston", new Integer(7)}
};

With that code, access the values like this:

Java Code:

System.out.println((String) foo[0][0]); // ouputs Boston
System.out.println((Integer) foo[0][1]); // ouputs 7

Notice that, because you have to type the array as Object (since you want to store Integers and Strings), you must cast them back to their original type.

After further consideration, a Map might be better for this. What is the integer for? Is that an ID, or some attribute of Boston?

the number 7 is an attribute for Boston which needs to be stored also at Instance 0

I was sure that this was done quite simply by something like this:

String abc[] = {
new String (Boston, 7);

is the above completely wrong or maybe I have some small syntax error ?

You'd be better off creating a class to group your data together.

Java Code:

class Foo {
    String str;
    int num;
    public Foo(String str, int num) {
        this.str = str;
        this.num = num;
    }
}
...
Foo[] fooArray = new Foo[2];
fooArray[0] = new Foo("Boston", 7);
fooArray[1] = new Foo("London", -34);

unfortunately still I am not getting any output from the below...


public class Foo {

public static void main(String[] args) {
}
String str;
int num;
public Foo(String str, int num) {
this.str = str;
this.num = num;
}



Foo[] fooArray = new Foo[2];{

fooArray[0] = new Foo("Boston", 7);

fooArray[1] = new Foo("London", -34);



System.out.println(fooArray[1]);

}

}

First and foremost, the above generates no output because your main() method contains no code.

Secondly, printing fooArray[1] will not produce the output you're expecting because Foo doesn't override toString(). Instead, it'll produce a string of what appears to be gibberish.

To be able to do anything meaningful with a Foo's fields, you'll need to do one of two things:

• Refer to the fields directly (usually considered bad practice). Example:
  
  Java Code:

  System.out.println(fooArray[1].str);

  Note that you'll only be able to do this if the class you're accessing the code from has access to the fields.
• Create getter/setter methods for each field (recommended). After creating such a method, you'd be able to do something like:
  
  Java Code:

  System.out.println(fooArray[1].getStringValue());

Create getter/setter methods for each field (recommended).

Were can I get help/examples of how to set these please ?

Originally Posted by aconti

unfortunately still I am not getting any output from the below...

Another classic example of people blindly copying code without understanding it and then whine when it doesn't do what they want.

Originally Posted by aconti

Create getter/setter methods for each field (recommended).

Were can I get help/examples of how to set these please ?

A setter or getter is just a method that either sets a class property to a value, or returns it. Here's a setter:

Java Code:

public void setString(String value) {
    this.str = value;
}

Here's a getter:

Java Code:

public string getString() {
    return this.str;
}

Originally Posted by Junky

Another classic example of people blindly copying code without understanding it and then whine when it doesn't do what they want.

What's wrong with that? Isn't that how programming is done nowadays? Personally I'm very advanced: when I copy and paste some stuff from teh net and it doesn't work I throw myself to the floor, start kicking around and scream on the top of my lungs until it's fixed.

kindest regards,

Jos

I'd pay money to see that!

Originally Posted by Junky

I'd pay money to see that!

Feeding times at 1:00pm; please don't stick your hands through the fence.

kind regards,

Jos

Originally Posted by JosAH

What's wrong with that? Isn't that how programming is done nowadays? Personally I'm very advanced: when I copy and paste some stuff from teh net and it doesn't work I throw myself to the floor, start kicking around and scream on the top of my lungs until it's fixed.

kindest regards,

Jos

You're one of my sons aren't you? Why aren't you in school?