Excellent, thanks. Adding 'first' to the other column labels is easy and makes sense to me.
One other question: currently to test the script I am writing, I am having to delete the jd files from outside of J. If I fail to do that, I get the error "|Jd error: table has ref: op:droptable db:csvload" when I re-run my script. In this context, I do not want to protect the data -- in this context, testing my script for unexpected dependencies is key. Is there some way of dropping that ref? Thanks, -- Raul On Thu, Feb 10, 2022 at 2:42 PM Eric Iverson <eric.b.iver...@gmail.com> wrote: > > Take a look at https://code.jsoftware.com/wiki/Jd if you have not already > done so. > > The docs are weak and we depend more on the tutorials. There are tutorials > that cover the area you are interested in. > > I loaded your files and have taken a quick look. > > First, I removed all the col relabel stuff as it is noise (and at times in > the past has triggered bugs). That is, remove all the txt: and other stuff > to make the statement as simple as possible. > > The by clause requires that there be an aggregation function for each col > in the select clause. That is the important part you were missing, although > the error was quite misleading. > > The following is a simple statement that works and has all the important > elements from your example. > > > jd'reads count patients.LASTNAME , count visits.VISIT_DATE by > patients.PATIENTID from patients, patients.visits' > > Perhaps it will help you get further along. > > If you get stuck again or are still stuck, please ask again. > > On Thu, Feb 10, 2022 at 2:12 PM Raul Miller <rauldmil...@gmail.com> wrote: > > > Embarrassing mis-statement: > > > > I wrote: "I am not trying to learn Jd" > > > > I meant: I am *now* trying to learn Jd > > > > -- > > Raul > > > > On Thu, Feb 10, 2022 at 1:58 PM Raul Miller <rauldmil...@gmail.com> wrote: > > > > > > http://rosettacode.org/wiki/Merge_and_aggregate_datasets > > > > > > After looking at this rosettacode task, I decided that Jd is probably > > > best suited for the J task implementation. So, I am not trying to > > > learn Jd (I had not had occasion to use it, previously). > > > > > > After a few minor mishaps, I've stumbled on an issue which I do not > > > know how to resolve. > > > > > > (Previous mishaps: csvload fails with an error suggesting that the > > > file does not exist if csvprepare has not been previously run. This > > > behavior is undocumented, except by example in the tutorials. Also, I > > > need to run the tutorial in a different J session from my testing work > > > to prevent the tutorials from breaking my tests.) > > > > > > Anyways, I'm currently getting an Unrecognized aggregate function > > > error, when trying to use the 'max' aggregate function. This should > > > demonstrate where I'm at: > > > > > > require'jd pacman' > > > load JDP,'tools/csv_load.ijs' > > > F=: jpath '~temp/rosettacode/example/CSV' > > > jdcreatefolder_jd_ CSVFOLDER=: F > > > > > > assert 0<{{)n > > > PATIENTID,LASTNAME > > > 1001,Hopper > > > 4004,Wirth > > > 3003,Kemeny > > > 2002,Gosling > > > 5005,Kurtz > > > }} fwrite F,'patients.csv' > > > > > > assert 0<{{)n > > > PATIENTID,VISIT_DATE,SCORE > > > 2002,2020-09-10,6.8 > > > 1001,2020-09-17,5.5 > > > 4004,2020-09-24,8.4 > > > 2002,2020-10-08, > > > 1001,,6.6 > > > 3003,2020-11-12, > > > 4004,2020-11-05,7.0 > > > 1001,2020-11-19,5.3 > > > }} fwrite F,'visits.csv' > > > > > > csvprepare 'patients';F,'patients.csv' > > > csvprepare 'visits';F,'visits.csv' > > > > > > csvload 'patients';1 > > > csvload 'visits';1 > > > > > > jd'ref patients PATIENTID visits PATIENTID' > > > > > > echo jd ([echo) deb {{)n > > > reads > > > p.PATIENTID, > > > LASTNAME:p.LASTNAME, > > > first v.VISIT_DATE > > > by > > > p.PATIENTID > > > from > > > p:patients, > > > v:p.visits > > > }} -.LF > > > > > > Now, ... one of my thoughts was that maybe this is a type error, > > > indicating that 'max' does not have a definition for the type of data > > > in this column. However, replacing 'max' with 'first' (which should be > > > defined for any type of column) also gives an "Unrecognized aggregate > > > function' error. > > > > > > So... > > > > > > (1) What am I doing wrong here, and > > > > > > (2) What should I have looked at to discover this information? > > > > > > Thanks, > > > > > > -- > > > Raul > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
