Re: exercise 2019/03

[Hans-Peter Sorge]

Hi,

this case should be all zeros:
      gradeDistri 'G'
A 0 100
B 0 100
C 0 100
D 0 100
F 0 100

looks ok:
      gradeDistri 'AG'
A 1 100
B 0   0
C 0   0
D 0   0
F 0   0

Regards
Hans-Peter

Am 17.04.20 um 17:29 schrieb Otto Diesenbacher-Reinmüller:
> Hi APLers,
>
> first, many thanks to Mohammad, Kacper and Hans-Peter for your hints
> regarding 2019/02. I learned a lot, and tried to incooperate in my
> solution for 2019/03, having had a deeper look in ∘.X, outer product!
>
> 3: Grade Distribution
> (https://www.dyalog.com/uploads/files/student_competition/2019_problems_phase1.pdf)
>
> "The school's administrative department wants to publish some simple
> statistics. Given anon-empty character vector of single-letter grades,
> produce a 3-column, 5-row,alphabetically-sorted matrix of each grade,
> the number of occurrences of that grade, andthe percentage (rounded to 1
> decimal position) of the total number of occurrences ofthat grade. The
> table should have a row for each grade even if there are no
> occurrencesof a grade. Note: due to rounding the last column might not
> total 100%.  Hint: The key operator ⌸ could be useful for this problem."
> (from the exercise)
>
> ∇table←gradeDistri grades;allgr
>    allgr←⍪'ABCDF'                      ⍝ all available grades
>    table←allgr,+/allgr ∘.= ,grades     ⍝ outer product =, and sum 1s up
>    table←table,+/table[;2]             ⍝ 3rd column with sum
>    table[;3]←10÷⍨⌊0.5+1000×table[;2]÷table[;3] ⍝ calculate col2÷col3 and round
>    ⍝ for sure, rounding could also be done
>    ⍝ with ⍕!
> ∇
>
> br & many thanks for any hint! - Otto
>
> --
> Dipl. Ing. (FH) Otto Diesenbacher-Reinmüller
> diesenbacher.net
> Salzburg, Österreich