Arrays

Array Reduce

Count With a Mask

Whole-array comparisons return a logical mask. count returns how many positions are .true..

Program

Play the program to count scores at or above 80.

array_reduce.f90 
program array_reduce
    implicit none
    integer :: scores(5)
    integer :: above
    scores = [65, 82, 91, 74, 88]
    above = count(scores >= 80)
    print '(I0)', above
end program array_reduce
logical mask `scores >= 80` produces a logical array.
count `count(mask)` returns the number of `.true.` positions.
whole array op Comparisons apply to every element at once.