Group Average - Modern Fortran Programming

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.
                            target_group
                            target_group = 1 (default)target_group = 2target_group = 3
                        

                            group_average.f90
                        
Replay: real traced execution (multi-file project)

                            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 = 1
    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 = 2
    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 = 3
    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

                        
1groups ← [1, 2, 1, 3, 2]⋯11groups = [1, 2, 1, 3, 2]12scores = [70, 80, 90, 90, 90]⋯values this step[1, 2, 1, 3, 2]groups
2scores ← [70, 80, 90, 90, 90]⋯11groups = [1, 2, 1, 3, 2]12scores = [70, 80, 90, 90, 90]13target_group = 1⋯values this step[70, 80, 90, 90, 90]scores
3target_group ← 1⋯12scores = [70, 80, 90, 90, 90]13target_group = 114count = 0⋯values this step1target_group
4count ← 0⋯13target_group = 114count = 015total = 0⋯values this step0count
5total ← 0⋯14count = 015total = 016do i = 1, 5⋯values this step0total
6i ← 1⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step1i
7if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.true.groups(1) == target_group
8count ← 1⋯17if (groups(i) == target_group) then18    count = count + 119    total = total + scores(i)⋯values this step0 → 1count
9total ← 70⋯18    count = count + 119    total = total + scores(i)20end if⋯values this step0 → 70total70scores(1)
10i ← 2⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step2i
11if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(2) == target_group
12i ← 3⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step3i
13if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.true.groups(3) == target_group
14count ← 2⋯17if (groups(i) == target_group) then18    count = count + 119    total = total + scores(i)⋯values this step1 → 2count
15total ← 160⋯18    count = count + 119    total = total + scores(i)20end if⋯values this step70 → 160total90scores(3)
16i ← 4⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step4i
17if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(4) == target_group
18i ← 5⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step5i
19if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(5) == target_group
20average ← 80⋯21end do22average = total / count23print '(I0, 1X, I0, 1X, I0)', target_group, count, average⋯values this step80average160total2count
21print '(I0, 1X, I0, 1X, I0)', target_group, count, average⋯22    average = total / count23    print '(I0, 1X, I0, 1X, I0)', target_group, count, average24end program group_average_demooutput1 2 80values this step1target_group2count80average
1groups ← [1, 2, 1, 3, 2]⋯11groups = [1, 2, 1, 3, 2]12scores = [70, 80, 90, 90, 90]⋯values this step[1, 2, 1, 3, 2]groups
2scores ← [70, 80, 90, 90, 90]⋯11groups = [1, 2, 1, 3, 2]12scores = [70, 80, 90, 90, 90]13target_group = 2⋯values this step[70, 80, 90, 90, 90]scores
3target_group ← 2⋯12scores = [70, 80, 90, 90, 90]13target_group = 214count = 0⋯values this step2target_group
4count ← 0⋯13target_group = 214count = 015total = 0⋯values this step0count
5total ← 0⋯14count = 015total = 016do i = 1, 5⋯values this step0total
6i ← 1⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step1i
7if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(1) == target_group
8i ← 2⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step2i
9if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.true.groups(2) == target_group
10count ← 1⋯17if (groups(i) == target_group) then18    count = count + 119    total = total + scores(i)⋯values this step0 → 1count
11total ← 80⋯18    count = count + 119    total = total + scores(i)20end if⋯values this step0 → 80total80scores(2)
12i ← 3⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step3i
13if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(3) == target_group
14i ← 4⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step4i
15if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(4) == target_group
16i ← 5⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step5i
17if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.true.groups(5) == target_group
18count ← 2⋯17if (groups(i) == target_group) then18    count = count + 119    total = total + scores(i)⋯values this step1 → 2count
19total ← 170⋯18    count = count + 119    total = total + scores(i)20end if⋯values this step80 → 170total90scores(5)
20average ← 85⋯21end do22average = total / count23print '(I0, 1X, I0, 1X, I0)', target_group, count, average⋯values this step85average170total2count
21print '(I0, 1X, I0, 1X, I0)', target_group, count, average⋯22    average = total / count23    print '(I0, 1X, I0, 1X, I0)', target_group, count, average24end program group_average_demooutput2 2 85values this step2target_group2count85average
1groups ← [1, 2, 1, 3, 2]⋯11groups = [1, 2, 1, 3, 2]12scores = [70, 80, 90, 90, 90]⋯values this step[1, 2, 1, 3, 2]groups
2scores ← [70, 80, 90, 90, 90]⋯11groups = [1, 2, 1, 3, 2]12scores = [70, 80, 90, 90, 90]13target_group = 3⋯values this step[70, 80, 90, 90, 90]scores
3target_group ← 3⋯12scores = [70, 80, 90, 90, 90]13target_group = 314count = 0⋯values this step3target_group
4count ← 0⋯13target_group = 314count = 015total = 0⋯values this step0count
5total ← 0⋯14count = 015total = 016do i = 1, 5⋯values this step0total
6i ← 1⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step1i
7if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(1) == target_group
8i ← 2⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step2i
9if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(2) == target_group
10i ← 3⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step3i
11if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(3) == target_group
12i ← 4⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step4i
13if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.true.groups(4) == target_group
14count ← 1⋯17if (groups(i) == target_group) then18    count = count + 119    total = total + scores(i)⋯values this step0 → 1count
15total ← 90⋯18    count = count + 119    total = total + scores(i)20end if⋯values this step0 → 90total90scores(4)
16i ← 5⋯15total = 016do i = 1, 517    if (groups(i) == target_group) then⋯values this step5i
17if (groups(i) == target_group) then⋯16do i = 1, 517    if (groups(i) == target_group) then18        count = count + 1⋯values this step.false.groups(5) == target_group
18average ← 90⋯21end do22average = total / count23print '(I0, 1X, I0, 1X, I0)', target_group, count, average⋯values this step90average90total1count
19print '(I0, 1X, I0, 1X, I0)', target_group, count, average⋯22    average = total / count23    print '(I0, 1X, I0, 1X, I0)', target_group, count, average24end program group_average_demooutput3 1 90values this step3target_group1count90average
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.