Test all values in a boolean[]

Question

I'm wondering if there is a more 'neat' way to test if all the values in a boolean array are true/false than iterating through the array and testing each individually like this:

for (boolean eval:booleanArray) {
    if (!eval) {
        return false;
    }
}

Essentially, i want to see if all of the values stored in an array of booleans is true, and if so, perform an action.

I'm pretty sure that there is some form of method for this, like array.contains(false) but i may be wrong.

It was a hastily thrown together example to illustrate the point but thanks — sh3rifme, Apr 18 '14 at 17:00

John B · Accepted Answer · 2014-04-18T18:20:19.630

4

Use Guava:

As pointed out by SotiriosDelimanolis

// verify all values are true
boolean result = !Booleans.contains(myArray, false);

Old post...

boolean result = Iterables.all(
         Booleans.asList(myArray),
         Predicates.equalTo(true));

Using statics it becomes:

boolean result = all(asList(myArray), 
                            equalTo(true));

Another options is using Sets

boolean result = Sets.newHashSet(Booleans.asList(myArray)).contains(true);

edited Apr 18 '14 at 18:20

answered Apr 18 '14 at 17:18

John B

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Cool solution, non-standart to say the least! – Denis Kulagin Apr 18 '14 at 17:21
@DenisKulagin LOL, and you think *my* method was complicated? You amuse me. – asteri Apr 18 '14 at 17:23
@SotiriosDelimanolis incorrect. Works just fine. Java takes care of the cast to `Boolean[]` for you. Just tried it to be sure. NP. – John B Apr 18 '14 at 17:53
Sorry, you are right. My Bad. I updated the post to use `Booleans.asList` – John B Apr 18 '14 at 18:01
Also, if you're using `Booleans`, you can just use its `contains` method. – Sotirios Delimanolis Apr 18 '14 at 18:04
Wow! Duh! 6 more to go – John B Apr 18 '14 at 18:18

asteri · Answer 2 · 2014-04-18T17:56:51.757

1

Use the List interface. It works thanks to the magic of autoboxing.

List<Boolean> values = new ArrayList<Boolean>();
// ...populate it ...
if(values.contains(false)) {
    //do something
}

edited Apr 18 '14 at 17:56

answered Apr 18 '14 at 17:03

asteri

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Converting to a List<> and wrapping primitives in a Boolean to do such a simple thing. No way) – Denis Kulagin Apr 18 '14 at 17:08
@DenisKulagin You should never be using primitive arrays to begin with. – asteri Apr 18 '14 at 17:20
@SotiriosDelimanolis Right you are. Forgot about primitive vs. object array casting, etc. – asteri Apr 18 '14 at 17:56

score 1 · Answer 3 · answered Apr 18 '14 at 17:07

1

It's definitely the fastest. And if you would like to neatinize it - extract to a separate method.

public static boolean testAllTrue(boolean[] booleanArray) {
  for (boolean eval : booleanArray) {
    if (!eval) {
        return false;
    }
  }
  return true;
}

answered Apr 18 '14 at 17:07

Denis Kulagin

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Nice in that it doesn't incur the cost of casting to `Boolean` as other solutions. Just pass in `boolean expected` as a parameter. – John B Apr 18 '14 at 17:24

Marco Acierno · Answer 4 · 2014-04-18T17:30:43.367

1

If you use Java8:

Some other ways:

long falseCount = Arrays.asList(arr).stream().filter(e -> !e).count();

If falseCount is 0, it means everything is true.

Or allMatch

boolean allTrue = Arrays.asList(arr).stream().allMatch(e -> e);

But using this system means:

Arrays.asList => Create a list, copy everything in the list
Wrap primite types to reference types (boolean -> Boolean)

Your foreach method, is the best method but if you already have items in a List why not use this?

edited Apr 18 '14 at 17:30

answered Apr 18 '14 at 17:21

Marco Acierno

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Big assumption that OP is using Java 8 – John B Apr 18 '14 at 17:28
Yes, but since other already have said the right solution why not be a bit creative with alternative solutions? – Marco Acierno Apr 18 '14 at 17:29
Would have just suggested a comment in your post that stated that solution required Java 8. The OP is obviously new to Java to ask this question. – John B Apr 18 '14 at 17:30
Oh, while i was writing this answer i added "If you use Java8" but i deleted it for error.. Thanks. – Marco Acierno Apr 18 '14 at 17:31
Assuming `arr` is a `boolean[]` this solution won't work in 7 or 8. – Sotirios Delimanolis Apr 18 '14 at 17:52
It works only if it is a Boolean[] right. – Marco Acierno Apr 18 '14 at 17:57
I'd ask you to add that detail in your answer. – Sotirios Delimanolis Apr 18 '14 at 17:57
You should add this as an answer to the duplicate question. – Samuel Edwin Ward May 19 '15 at 16:13

Test all values in a boolean[]

4 Answers4