SAS: How to use RETAIN statement to create a summed variable in the DATA step, equivalent to the SUM statement output in PROC PRINT - sum

Question

In SAS, I'm trying to create a variable that is the sum of another. In this case, I am trying to create two variables: Total_All_Ages, which is the sum of the 2013 US population POPESTIMATE2013, and Total_18Plus, which is the sum of the 2013 US population aged 18+ POPEST18PLUS2013.
I want the output of these variables to appear as though I had used the sum statement under proc print (where the sum appears at the bottom of the variable column in a new row). However, I do not want to use the print procedure. Instead, I want to create my output only using the data step.
The way I need to do this is with the retain (and input) statement.
My code is as follows:
data _NULL_;
retain Total_All_Ages Total_18Plus;
infile RAWfoldr DLM=',' firstobs=3 obs=53;
informat STATE $2. NAME $20.;
input SUMLEV REGION $ DIVISION STATE $ NAME $ POPESTIMATE2013 POPEST18PLUS2013 PCNT_POPEST18PLUS;
Total_All_Ages = sum(Total_All_Ages, POPESTIMATE2013);
Total_18Plus = sum(Total_18Plus, POPEST18PLUS2013);
keep STATE NAME POPESTIMATE2013 POPEST18PLUS2013 Total_All_Ages Total_18Plus;
format POPESTIMATE2013 comma11. POPEST18PLUS2013 comma11.;
file print notitles;
if _n_=1 then put '=== U.S. Resident Population Estimates for All Ages and ===
Ages 18 or Older by State (in Alphabetical Order), 2013';
if _n_=1 then put ' ';
if _n_=1 then put #5 'FIPS Code' #16 'State Name' #40 'All Ages' #55 'Ages 18 or Older';
if _n_=1 then put ' ';
put #5 STATE #16 NAME #40 POPESTIMATE2013 #55 POPEST18PLUS2013;
run;
You can see that in my input statement, I create the two variables that I mentioned. I also mention them in my retain statement. However, I'm not sure how to make them appear in my output in the way I specified.
I want them to appear as a Total line at the bottom of the output, like this:
POPESTIMATE2013 POPEST18PLUS2013
112312234 1234123412341234
23413412341234 213412341234
============ ============ ============
Total 23423423429 242234545345
Is there a way to put these variables on a new line at the very bottom of the output (sort of like how I put the variable labels using the if _n_=1 code)?
Let me know if I need to explain myself better. I appreciate any help with this. Thank you.

Answer 1

If I understand your question, you're almost there.
First, add end=eof to your infile statement. This initializes a variable "eof" that is equal to 0, but will equal 1 only when SAS is reading in the last line of data. This works in a set statement as well.
Next, add this do block, which will execute when sas is on the last line of the file:
if eof then do;
put #5 9*'=' #40 11*'=' #55 11*'=';
put #5 'Total' #40 Total_All_Ages comma11. #55 Total_18Plus comma11.;
end;
Here, you use put statements to print out the formatting (repeated ='s signs) and the totals. Complete code is below:
data _NULL_;
retain Total_All_Ages Total_18Plus;
infile RAWfoldr DLM=',' firstobs=3 obs=53 end=eof;
informat STATE $2. NAME $20.;
input SUMLEV REGION $ DIVISION STATE $ NAME $ POPESTIMATE2013 POPEST18PLUS2013 PCNT_POPEST18PLUS;
Total_All_Ages = sum(Total_All_Ages, POPESTIMATE2013);
Total_18Plus = sum(Total_18Plus, POPEST18PLUS2013);
keep STATE NAME POPESTIMATE2013 POPEST18PLUS2013 Total_All_Ages Total_18Plus;
format POPESTIMATE2013 comma11. POPEST18PLUS2013 comma11.;
file print notitles;
if _n_=1 then put '=== U.S. Resident Population Estimates for All Ages and ===
Ages 18 or Older by State (in Alphabetical Order), 2013';
if _n_=1 then put ' ';
if _n_=1 then put #5 'FIPS Code' #16 'State Name' #40 'All Ages' #55 'Ages 18 or Older';
if _n_=1 then put ' ';
put #5 STATE #16 NAME #40 POPESTIMATE2013 comma11. #55 POPEST18PLUS2013 comma11.;
if eof then do;
put #5 9*'=' #40 11*'=' #55 11*'=';
put #5 'Total' #40 Total_All_Ages comma11. #55 Total_18Plus comma11.;
end;
run;
One final note on your code: you can right-align your numbers by specifying a format followed by "-r" in your put statement, e.g.:
put #5 STATE #16 NAME #40 POPESTIMATE2013 comma11.-r #55 POPEST18PLUS2013 comma11.-r;
This will override any format statement you have.