Create dummy variables SAS - sas

Question

I have a dataset, say "dataset", and it is composed by two variables, say "id" and "text".
in the variable "text" I may have something like "A" or "A, B" or "A, B, C" or "D" (or any possible combination of the 4 letters, see the image). what I want at the end of the day is a dataset with dummy variables, so something like text_A where text_A contains 1 if A is in text and so on.
Now I have written some code that actually doesn't work:
this creates the "dummified" dataset, and it works
DATA dummified_dataset;
SET starting_dataset;
text_A = 0;
text_B = 0;
text_C = 0;
text_D = 0;
RUN;
here it is my code to do the job:
DATA want;
SET dummified_dataset;
DO i = 1 TO COUNTW(text, ",");
%LET var_text = SCAN(text, i, ",");
IF &var_text = "A" OR &var_text = "a" THEN text_A = 1;
IF &var_text = "B" OR &var_text = "b" THEN text_B = 1;
IF &var_text = "C" OR &var_text = "c" THEN text_C = 1;
IF &var_text = "D" OR &var_text = "d" THEN text_D = 1;
END;
RUN;
with the code above it seems to process only the first element: if a row contains text = "A,B,C,D" only text_A is put to 1 and the others remain to 0

Answer 1

Good start but not sure why you switched to macro logic halfway through.
First take your data set and create a new row for each letter attached to the ID instead of trying to deal with it in the current structure.
Then use PROC FREQ which will generate that table above but not in a data set. The data set will need to be restructured if you want it in that output. For that step, use PROC TRANSPOSE to get your final structure.
DATA long;
SET dummified_dataset;
DO i = 1 TO COUNTW(text, ",");
var_text = SCAN(text, i, ",");
output;
END;
RUN;
proc freq data=long;
table id*var_text / out=long_freq sparse nopercent nocol norow;
run;
proc transpose data=long out=long_freq;
by id;
id var_text;
var count;
run;