calculate number of true (or false) elements in a bool array?

Question

Suppose I have an array filled with Boolean values and I want to know how many of the elements are true.

private bool[] testArray = new bool[10] { true, false, t         


        

Answer 1

I like this:

int trueCount = boolArray.Sum( x  => x ? 1 : 0 ) ;

Answer 2

Use LINQ. You can do testArray.Where(c => c).Count(); for true count or use testArray.Where(c => !c).Count(); for false check

Answer 3

You can use:

int CalculateValues(bool val)
{
    return testArray.Count(c => c == val);
}

This handles the true and false checks, based on your val parameter.

Answer 4

Try something like this :

bool[] testArray = new bool[10] { true, false, true, true, false, true, true, true, false, false };
bool inVal = true;
int i;

i = testArray.Count(ai => ai == inVal);

Answer 5

return testArray.Count(c => c)

Answer 6

While testArray.Count(c => c) is functionally correct, it's not intuitive and there's a risk that some later developer will strip out the c => c part thinking it doesn't do anything.

This can be derisked by declaring the lambda function separately with a meaningful name:

Func<bool, bool> ifTrue = x => x;
return testArray.Count(ifTrue);