How to manually set a boolean array in just one code line (Java)?

Question

How do you manually assign a boolean value to every array positions in just one code line?

Look the code fragment below. I don't wanna manually put a[0]=true; a[1]=true; a[2]=false; ...

public class stackArray {

   static boolean [] a = new boolean [6];

   public static void main(String[] args) {

      a[0]=true;
      a[1]=true;
      a[2]=false;

      for(int i=0; i<6; i++){
         System.out.println(a[i]);
      }

   }
}

I'm really looking something similar to

a= {true, true, false, false, false, false};

but unfortunately it doesn't works :(

Can anybody help me? I googled it but I couldn't find this particular case. Thank you in advance!

`static boolean [] a = new boolean [6]{true, true, false, false, false, false};` should work. Check top answer to [this question](https://stackoverflow.com/questions/1200621/how-do-i-declare-and-initialize-an-array-in-java). — AntonH, Sep 11 '17 at 15:29
@AntonH That will not compile. You probably meant `static boolean[] a = { true, true, false, false, false, false };`. — VGR, Sep 11 '17 at 16:27
@VGR You're right that it won't compile, but just removing the `6` is enough to make it compile. I didn't test before posting, which is my mistake. Maybe not necessary, but close to OP's original code. — AntonH, Sep 11 '17 at 16:36

score 0 · Answer 1 · answered Sep 11 '17 at 15:29

0

use the fill method in the Arrays helper class

boolean[] a = new boolean[6];
Arrays.fill(a, true);

answered Sep 11 '17 at 15:29

ΦXocę 웃 Пepeúpa ツ

43,054
16
58
83

2

OP doesn't want all `true` values, though. – AntonH Sep 11 '17 at 15:30
ummm.... what do you mean? OP wrote ***to every array positions....*** – ΦXocę 웃 Пepeúpa ツ Sep 11 '17 at 15:32
I mean that in the example array he provided, the different elements of the array don't all have the same value. Some are `true`, some are `false`. Your answer sets all elements to `true`. – AntonH Sep 11 '17 at 15:33
@AntonH is right. Anyways, thank you guys for your help! I found the solution in other answer – 0xGolovkin Sep 11 '17 at 16:05

score 0 · Answer 2 · answered Sep 11 '17 at 15:33

If the array reference is not shared in some other variable then you can just reassign to a new array:

a = new boolean[] {true, .. };

Otherwise if you really want it in one line while keeping the array the same you can do

System.arrayCopy(new boolean[] { true, ... }, 0, a, 0, a.length };

but it doesn't look like better.

score 0 · Answer 3 · answered Sep 11 '17 at 15:34

0

You can do it like this:

boolean [] a = new boolean []{false, false, true};

answered Sep 11 '17 at 15:34

Julio Daniel Reyes

3,281
15
20

Thank you Julio, that was exactly what I was looking for, is simple but I couldn't get it! – 0xGolovkin Sep 11 '17 at 16:06
You don’t need the `new boolean[]` at all. – VGR Sep 11 '17 at 16:24

How to manually set a boolean array in just one code line (Java)?

3 Answers3