How to create an ArrayList<Double>?

Question

I'm doing an assignment for class that requires me to create a class that extends ArrayList<Double>. However I cannot make an ArrayList<Double> without getting an error.

I created a new class to try and test it and it still doesn't work. Here's what I have:

import java.util.ArrayList;

public class imSad {

   ArrayList<Double> var = new ArrayList<Double>();

   var.add(double 15.0);

   var.add(15.0);

However this gives me the error : Syntax Error on token "15.0" invalid VariableDeclaratorID and Syntax Error on token "add" Identifier expected after this token.

What am I doing wrong? I've tried searching it but I'm having trouble finding much on arraylists of doubles.

Why would you expect this line - var.add(double 15.0); to compile? — Rohit Jain
– Rohit Jain, Commented Nov 25, 2013 at 8:29
Just remove the word double from before 15.0. Everything else is perfect. — Dawood ibn Kareem
– Dawood ibn Kareem, Commented Nov 25, 2013 at 8:29
I've tried searching it but I'm having trouble finding much on arraylists of doubles. Typing 'arraylist of doubles' (google) gives you examples when clicking just the second link - took me ~10s to find. — Artur
– Artur, Commented Nov 25, 2013 at 8:38

duffy356 · Accepted Answer · 2013-11-25 08:34:32Z

3

the cast is wrong.

use

var.add((double) 15.0);

or

var.add(15.0d);

or better, by default

var.add(15.0);

edited Nov 25, 2013 at 8:34

answered Nov 25, 2013 at 8:29

duffy356

3,7163 gold badges35 silver badges48 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Rohit Jain Over a year ago

Isn't 15.0 a double type by default?

Dawood ibn Kareem Over a year ago

Don't do this. 15.0 is already a double. It's completely redundant either to cast it, or to affix the d.

Rahul · Accepted Answer · 2013-11-25 08:30:09Z

1

You can assign the value to a double variable and then add it.

double val = 15.0; // create a double variable
var.add(val); // add it to the list
..
var.add(15.0); // add it without creating a new double variable, which you already did

Also, by default 15.0 is double and thus you need not cast it.

answered Nov 25, 2013 at 8:30

Rahul

45.2k11 gold badges89 silver badges108 bronze badges

Comments

creichen · Accepted Answer · 2013-11-25 08:32:12Z

1

You don't need a cast to write double literals in Java; all floating-point literals are double by default (JLS7, 3.10.2). So just writing

var.add(15.0);

is entirely sufficient.

answered Nov 25, 2013 at 8:32

creichen

1,7689 silver badges16 bronze badges

Comments

masoud · Accepted Answer · 2013-11-25 08:32:20Z

1

Just add doubles like this, you don't need casting:

var.add(15.0);

answered Nov 25, 2013 at 8:32

masoud

56.8k18 gold badges152 silver badges214 bronze badges

Comments

Martin Seeler · Accepted Answer · 2013-11-25 08:35:51Z

1

if you wanna cast it, you should write

var.add((double) 15.0);

or

var.add(15.0d);

if you write

var.add(double 15.0);

it is a declaration of a new double, which you will name 15.0 (which is not valid, because you can't start a variable name with a number and it can not contain a dot.)

edited Nov 25, 2013 at 8:35

answered Nov 25, 2013 at 8:29

Martin Seeler

7,0023 gold badges36 silver badges46 bronze badges

Comments

Satheesh Cheveri · Accepted Answer · 2013-11-25 10:08:27Z

1

You may try this,

import java.util.ArrayList;

public class YouShouldResearch{

public static void main(String ar[]) {
     ArrayList<Double> var = new ArrayList<Double>();
     var.add(15.0);

}
}

answered Nov 25, 2013 at 10:08

Satheesh Cheveri

3,7093 gold badges29 silver badges47 bronze badges

Comments

masoud · Accepted Answer · 2013-11-25 19:50:33Z

0

var.add(15.0);

should be OK. Or

var.add((double)15.0);

edited Nov 25, 2013 at 19:50

masoud

56.8k18 gold badges152 silver badges214 bronze badges

answered Nov 25, 2013 at 8:29

eMko

1,1439 silver badges22 bronze badges

Collectives™ on Stack Overflow

How to create an ArrayList<Double>?

7 Answers 7

2 Comments

Comments

Comments

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

2 Comments

Comments

Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related