How to prefix array element to create dynamic variable

[zqkal]

Hello SAS Users, 

I need to create a dynamic variable by adding prefix into an array element. I have a SAS dataset and i need to create a running total for each variables. However,  i keep getting an error related to array ref doesn't exist. I don't want to hard code the variable names as new variable names will be added into the dataset every month. 

here is the SAS code i'm running

data have;

input id FAS_1990_01 FAS_1991_01 FAS_1991_02 FAS_1991_03 FAS_1992_01 FAS_1992_02 FAS_1992_03 FAS_1993_01; 

datalines; 

1 7983 1000 1200 3099 7083 1009 1900 7099

2 9000 1500 1300 4390 7983 1080 1280 3199

3 3898 3090 1400 4980 7973 1050 1260 3299

4 4654 2483 1500 3879 7953 1080 1400 3899

;

run;

data need; 

set have; 

by id; 

array deal_sum{*} FAS:; 

do i = 1 to dim(total); 

total_||deal_suml{i}  + deal_sum{i}; 

end; 

run;

[art297]

Given your example dataset, what do you want the resulting dataset to look like?

Art, CEO, AnalystFinder.com

[zqkal]

This will creat the desired output. 

data need;
set have;
by id;
total_FAS_1990_01 + FAS_1990_01;
total_FAS_1991_01 + FAS_1991_01;
total_FAS_1991_02 + FAS_1991_02;
total_FAS_1991_03 + FAS_1991_03;
total_FAS_1992_01 + FAS_1992_01;
total_FAS_1992_02 + FAS_1992_02;
total_FAS_1992_03 + FAS_1992_03;
total_FAS_1993_01 + FAS_1993_01;
run;

[Astounding]

Your code assumes you have an array named TOTAL.  You can create one, but you would need to identify the variables in it.  Since you have but a few, it might be simplest to hard-code the names:

data need; 

set have; 

by id; 

array deal_sum{*} FAS:; 

array total {*} total_FAS_1990_01 total_FAS_1991_01 total_FAS_1991_02 total_FAS_1991_03

   total_FAS_1992_01 total_FAS_1992_02 total_FAS_1992_03 total_FAS_1993_01;

do i = 1 to dim(total); 

total{i}  + deal_sum{i}; 

end; 

run;

If your actual data set contains more variables, you can use macro language to construct the set of names.  But for 8 variable names, why complicate the program?

[Reeza · Accepted solution]

Can you store your data in a long form instead of wide? This violates the best practice of not having 'data' in your column headers. 

Its also easier to add rows to a dataset versus adding columns. For the running total, if you have SAS/ETS look at PROC EXPAND.