CODEWITHSUNDEEP
arraysarraylistprocessing
user1767774
user1767774

Reputation: 1825

how to get a boolean from ArrayList in processing

I have an ArrayList, "list", that contains one value, true. However, when i write:

if (list.get(0)==true)

I get the error "incompatible operand types Object and boolean". Is ArrayList.get() method always return object? if so, how can I get the boolean value?

thanks.

Upvotes: 1

Views: 8530

Answers (3)

TheEwook
TheEwook

Reputation: 11117

If your list always contains booleans I suggest you type your arraylist as boolean

List<Boolean> list = ArrayList<Boolean> ();

And now you are able to do what you want to do:

if (list.get(0))

For information:

if (list.get(0)==true) and if (list.get(0)) are identical.

if you cannot use generics you can cast

if((Boolean) list.get(0))
{
    System.out.println("OK");
}

Upvotes: 5

Otacon
Otacon

Reputation: 342

You can try to create a var to verify if the "if" statement will be true like this:

for(int i = 0; i < aList.size();i++){ match = aList.get(i).equals("Red"); System.out.print(match); }

The match variable will receive the Boolean value of this comparison.

Regards,

Otacon.

Upvotes: 2

Pablo Lozano
Pablo Lozano

Reputation: 10342

Yes, ArrayList stores objects and it cannot know the class, unless you use generics.

So you have two options: Generics or casting every "get".

With casting:

if ( ((Boolean)list.get(0))==true ) { ... }

With generics, declare list as:

List<Boolean> list= new ArrayList<>();
list.add(true);

if (list.get(0)) { // list.get(0)==true is unnecesary
...
}

Upvotes: 2

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