asked on

how to find out if an array contains all true or all false or partially true

Just a general programming question, i am looking for the most elegant way to solve this. Ideally if it's partially true and partially false, I want to break out of the loop before the entire array is looped thru. Thanks.

dpearson

Here's one way:

boolean first = array[0] ;

for (int i = 1 ; i < array.length) {
   if (array[i] != first)
      throw new Exception("Mixed") ;
}

// By here all elements must match first (true or false)
return first ;

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Tom Beck

All programing languages provide some way of breaking out of a loop before it finishes. Most often it's done with the keyword break;.

Example:

for (var i = 0; i < someArray.length; i++) {
   if (someCondition) {
       break;   // exit the loop before it completes
   }
   // do something else when the condition if false
}

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SOLUTION

awking00

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dpearson

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SOLUTION

phoffric

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dpearson

Since the OP did ask for the most elegant solution, dare we go into Java 8?

boolean[] array ;

long same = IntStream.range(0, array.length-1).
            filter(i -> array[i] == array[i+1]).
            count();

System.out.println(same == array.length-1 ? "All " + array[0] : "Mixed") ;

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phoffric

>> dare we go into Java 8?
Well, looking at the author's history of Java questions, I didn't think so; but then again, looking further back, there are many C# questions, so maybe yes.