@teelov wrote:
i have an number of datasets, ranging from 1000 rows to 300,000,000, 10 variables to 256
on a proceedings paper i read that:
1 % - 15% An index will definitely improve program performance
16% - 20% An index will probably improve program performance
so with that in mind i need to ask the question and create some code which:
Returns a list of variables that meet the criteria where then number of distinct values on given variables that amount to 20% or less of the total row count of that table
I'm not sure how to approach this as it will take some stress on the server if i just use proc freq?
advice?
I would be tempted to start with proc freq with the nlevels option which reports the number of non-missing and missing levels for variables. Candidates would be those that have no missing levels and relatively large number of non-missing levels.
Example:
ods select nlevels;
Proc freq data=sashelp.class nlevels;
run;
The ods select only displays the neleves information. You can use the ODS OUTPUT to save that into a data set if needed.
I would look for variables that are more categorical in nature, such as NAME in the above, than measured such as HEIGHT.
