get rows where: speed issue

[hogi]

☐ cool new feature
☑ could help many users!

☑ removes a „bug“

☐ nice to have

☐ nobody needs it

#myTop10_2022

Get rows where is extremely slow if the column is referenced with a varible (here i=5 )

dt = Open( "$SAMPLE_DATA/Wafer Stacked.jmp" );
t0=hptime();
i = 5;
dt << get rows where( As Column( dt, i ) == 10 );
(hptime()-t0)/1000000;

instead of a direct reference like in

dt << get rows where( As Column( dt, 5 ) == 10 );

My wishes:

• Is it possible to "fix this issue in the background"?
  e.g. by a setting in the preferences:
  "hereby I confirm that JMP is allows to pre-evaluate variables to speed up code execution - accepting that this could lead to unintended/unusual behavior"
  (I am not good enough in JSL programming to predict all the collateral effects - would such a mode make sense?)
• If fixing the issue in the background is not possible, could you please implement a warning function in JSL such that the user gets informed about the bad performance due to non-pre-evaluated variables. Then he can adjust the code,
  with substitute
  Should you Loop through a data table or use Recode, or use Get Rows Where to change values in a data... 
  or Eval:
  https://community.jmp.com/t5/Discussions/Should-you-Loop-through-a-data-table-or-use-Recode-or-use-G... 
  
  

more wishes submitted by  

[Sarah-Sylvestre]

Hi @hogi, thank you for your suggestion! We have captured your request and will take it under consideration.

[hogi]

Thanks :)

[hogi]

hi Sarah. Is there an update?

If not, I can live without : )

[Sarah-Sylvestre]

Hi @hogi, I apologize for not responding to your earlier message! If you want to be sure I will get a notification, please tag me. In JMP 18, there is a new JSL function Where that is a replacement for dt << Get Rows Where. Please check it out and let me know if it solves your issue. For now, I have marked this as Delivered.

[hogi]

hi @Sarah-Sylvestre 

the above code gives 4625 matching rows, when I try it with

dt = Open( "$SAMPLE_DATA/Wafer Stacked.jmp" );
t0=hptime();
i = 5;
where(dt,  As Column( dt, i ) == 10 );
(hptime()-t0)/1000000;

I get

Can Where() be used for this application? how?