Is it possible to select/keep columns in SAS by using an index like in R? (e.g., I want to keep columns 2 through 5 in a dataset with 10 variables). I want to do this without specifying the names (e.g., keep x1 x2 x3).
In R, to see only those columns (without knowing the column names), I would type x[,2:5]
You could use proc sql to create a macro variable. e.g.:
proc sql;
select name
into :vars separated by ' '
from dictionary.columns
where libname="SASHELP" and /*must be upper case*/
memname="CLASS" and /*must be upper case*/
varnum between 2 and 5
;
quit;
data want;
set sashelp.class (keep=&vars.);
run;
You could use proc sql to create a macro variable. e.g.:
proc sql;
select name
into :vars separated by ' '
from dictionary.columns
where libname="SASHELP" and /*must be upper case*/
memname="CLASS" and /*must be upper case*/
varnum between 2 and 5
;
quit;
data want;
set sashelp.class (keep=&vars.);
run;
An interesting question. If you know the 2nd and 5th names, you can use the -- operator to get the variable names between them. I didn't know how to do the general case, but I found a useful paper by Stephanie Thompson that describes how to use PROC SQL to do this operation: http://analytics.ncsu.edu/sesug/2006/CC01_06.PDF
Here is one solution:
proc contents data = Sashelp.Cars noprint out=vars(keep = varnum name);
run;
proc sql noprint;
select name
into :keepvars separated by ' '
from vars
where 2 <= varnum <= 5
order by varnum;
quit;
%put &keepvars;
data subset;
set Sashelp.Cars;
keep &keepvars;
run;
Thanks Art and Rick for the answers! Both solutions work (I was hoping for a solution that didn't use SQL but that's fine).
Hi ,
Here is an approach of getting the desired output but from datastep without the use of proc sql.
data class;
set sashelp.class;
run;
data columns;
set sashelp.vcolumn;
where libname='WORK' and memname='CLASS' and 2<=varnum<=5;
call symputx("keep"||trim(put(varnum,1.)),name);
run;
%put &keep2 &keep3;
%macro vars;
data class1;
set class;
keep %do j=2 %to 5; &&keep&j %end;;
run;
%mend;
%vars
hope it helps.
Thanks,
Jag
If you want to treat a series of variables as if they form a matrix then why not just name them using numeric suffixes? Such X1-X10. Then it is as easy to select as typing in the index numbers. You can use the LABELS to store more meaning information about the variables.
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