Statistical Summaries

Group Average

Filtering Rows Before Summing

A grouped summary filters rows by group before it counts and sums them.

Program

Play the program to choose which group contributes to the average.

group_average.f90 
program group_average_demo
    implicit none
    integer :: groups(5)
    integer :: scores(5)
    integer :: target_group
    integer :: i
    integer :: count
    integer :: total
    integer :: average

    groups = [1, 2, 1, 3, 2]
    scores = [70, 80, 90, 90, 90]
    target_group = 
    count = 0
    total = 0
    do i = 1, 5
        if (groups(i) == target_group) then
            count = count + 1
            total = total + scores(i)
        end if
    end do
    average = total / count
    print '(I0, 1X, I0, 1X, I0)', target_group, count, average
end program group_average_demo

program group_average_demo
    implicit none
    integer :: groups(5)
    integer :: scores(5)
    integer :: target_group
    integer :: i
    integer :: count
    integer :: total
    integer :: average

    groups = [1, 2, 1, 3, 2]
    scores = [70, 80, 90, 90, 90]
    target_group = 
    count = 0
    total = 0
    do i = 1, 5
        if (groups(i) == target_group) then
            count = count + 1
            total = total + scores(i)
        end if
    end do
    average = total / count
    print '(I0, 1X, I0, 1X, I0)', target_group, count, average
end program group_average_demo

program group_average_demo
    implicit none
    integer :: groups(5)
    integer :: scores(5)
    integer :: target_group
    integer :: i
    integer :: count
    integer :: total
    integer :: average

    groups = [1, 2, 1, 3, 2]
    scores = [70, 80, 90, 90, 90]
    target_group = 
    count = 0
    total = 0
    do i = 1, 5
        if (groups(i) == target_group) then
            count = count + 1
            total = total + scores(i)
        end if
    end do
    average = total / count
    print '(I0, 1X, I0, 1X, I0)', target_group, count, average
end program group_average_demo
group filter Only rows whose group matches `target_group` enter the summary.
count and total The same branch increments the row count and adds the score.
integer average This example keeps the average as an integer for compact output.