topic Re: Macro Variables with Multiple Ampersands in SAS Programming

Macro Variables with Multiple Ampersands

djbateman — Wed, 01 Nov 2017 18:20:48 GMT

Okay. This is getting on my nerves. Just when I think I know how to access macro variables with multiple ampersands, something goes wrong. Can someone correct my code so I can display the values 7 and 624? I have tried all kinds of combinations of ampersands and periods, but the closest I can get it to display "BRON_BRON_R1_TERM_CNT" and "CM_TERM_CNT" instead of "7" and "624".

%let dsname1=BRON_BRON_R1;
%let dsname2=CM;

%let BRON_BRON_R1_TERM_CNT=7;
%let CM_TERM_CTN=624;


%macro loop;
	%do i=1 %to 2;
		%put &&&&dsname&i.._TERM_CNT;
	%end;
%mend loop;

%loop;

Re: Macro Variables with Multiple Ampersands

Astounding — Wed, 01 Nov 2017 18:32:17 GMT

If you cut down the number of & from 4 down to 2, you should be fine.

Re: Macro Variables with Multiple Ampersands

djbateman — Wed, 01 Nov 2017 18:37:04 GMT

That doesn't work for me. I get the values "BRON_BRON_R1_TERM_CNT" and "CM_TERM_CNT" instead of "7" and "624".

Using && converts &&dsname&i. to &dsname1, which converts to BRON_BRON_R1, so I am left with BRON_BRON_R1_TERM_CNT. I now need SAS to recognize &BRON_BRON_R1_TERM_CNT, which is why I added the extra && in front.

If i use &&dsname&i.._TERM_CNT, I get:

MLOGIC(LOOP):  Beginning execution.
MLOGIC(LOOP):  %DO loop beginning; index variable I; start value is 1; stop value is 2; by value is
      1.
MLOGIC(LOOP):  %PUT &&dsname&i.._TERM_CNT
SYMBOLGEN:  && resolves to &.
SYMBOLGEN:  Macro variable I resolves to 1
SYMBOLGEN:  Macro variable DSNAME1 resolves to BRON_BRON_R1
BRON_BRON_R1_TERM_CNT
MLOGIC(LOOP):  %DO loop index variable I is now 2; loop will iterate again.
MLOGIC(LOOP):  %PUT &&dsname&i.._TERM_CNT
SYMBOLGEN:  && resolves to &.
SYMBOLGEN:  Macro variable I resolves to 2
SYMBOLGEN:  Macro variable DSNAME2 resolves to CM
CM_TERM_CNT
MLOGIC(LOOP):  %DO loop index variable I is now 3; loop will not iterate again.
MLOGIC(LOOP):  Ending execution.

If I use &&&&dsname&i.._TERM_CNT, I get the exact same thing:

MLOGIC(LOOP):  Beginning execution.
MLOGIC(LOOP):  %DO loop beginning; index variable I; start value is 1; stop value is 2; by value is
      1.
MLOGIC(LOOP):  %PUT &&&&dsname&i.._TERM_CNT
SYMBOLGEN:  && resolves to &.
SYMBOLGEN:  && resolves to &.
SYMBOLGEN:  Macro variable I resolves to 1
SYMBOLGEN:  && resolves to &.
SYMBOLGEN:  Macro variable DSNAME1 resolves to BRON_BRON_R1
BRON_BRON_R1_TERM_CNT
MLOGIC(LOOP):  %DO loop index variable I is now 2; loop will iterate again.
MLOGIC(LOOP):  %PUT &&&&dsname&i.._TERM_CNT
SYMBOLGEN:  && resolves to &.
SYMBOLGEN:  && resolves to &.
SYMBOLGEN:  Macro variable I resolves to 2
SYMBOLGEN:  && resolves to &.
SYMBOLGEN:  Macro variable DSNAME2 resolves to CM
CM_TERM_CNT
MLOGIC(LOOP):  %DO loop index variable I is now 3; loop will not iterate again.
MLOGIC(LOOP):  Ending execution.

BUT WHY!!!

Re: Macro Variables with Multiple Ampersands

Astounding — Wed, 01 Nov 2017 18:46:06 GMT

Sorry, I read the problem wrong. Is it that your original code is correct, except for switching the "TN" vs. "NT" in the %LET statement?

********************

EDITED:

Besides that, I think you need to use 6 ampersands.

Re: Macro Variables with Multiple Ampersands

djbateman — Wed, 01 Nov 2017 18:54:18 GMT

Oh, good catch on the misspelling. But that obviously wasn't the problem since BRON_BRON_R1_TERM_CNT wasn't misspelled.

Still, I tried the 6 ampersands, and that seems to have done it. I can never tell how many to use. I've never needed more than 4, so I never went beyond that.

Thank you so much!

Re: Macro Variables with Multiple Ampersands

PaigeMiller — Wed, 01 Nov 2017 19:22:24 GMT

You could make your life a whole lot simpler if you just didn't have to have _TERM_CNT at the end of the macro variable names. You could even put TERM_CNT_ at the beginning to achieve this simplicity.

Re: Macro Variables with Multiple Ampersands

AlanC — Thu, 02 Nov 2017 00:48:26 GMT

My breaking point was 5. I basically changed my approach to macros that night.

When macros get really complex, consider spooling the problem out and then including it back in.

data _null_ ;

file myFile;

do i = 1 to 3 ;

put 'test_' i ;

end;

run;

%include myFile;

Simplifies debugging TREMENDOUSLY. There are other ways than that too: just get creative...but readable.