topic the value of the resolved macro variable in SAS Programming

the value of the resolved macro variable

steve_citi — Fri, 07 Oct 2011 07:13:32 GMT

If I have a macro variable which resolves to a variable name, how do I print the value of the variable?

For example, if my macro variable is &&name&i. and when i=2 then &name2 resolves to acct_num, then how do I print the value of acct_num.

put "&&name&i."; only prints the literal acct_num, not its value.

Is there any way to do this?

the value of the resolved macro variable

DF — Fri, 07 Oct 2011 08:08:45 GMT

Assuming I've understood correctly, you should drop the quotes and add an extra ampersand. The quotes will force it to show the variable name instead of decoding it.

%let name=var;

%let num=2;

%let var1=account;

%let var2=acct_num;

data z;

acct_num = "asdf";

put &&&name.&num.;

run;

My log then shows:

68 data z;

69 acct_num = "asdf";

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable NAME resolves to var

SYMBOLGEN: Macro variable NUM resolves to 2

SYMBOLGEN: Macro variable VAR2 resolves to acct_num

71 put &&&name.&num.;

72 run;

NOTE: The data set WORK.Z has 1 observations and 1 variables.

NOTE: DATA statement used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

the value of the resolved macro variable

sas_new — Fri, 07 Oct 2011 10:47:24 GMT

Hi Steve,

I think you can do this way...

%let name=var;

%let num=2;

%let var1=account;

%let var2=acct_num;

%put &&&name&num;

Thanks,

Kuthubudeen

the value of the resolved macro variable

ChrisSelley — Fri, 07 Oct 2011 11:48:19 GMT

Hi Steve

I think you're getting bogged down with ampersands - it's just

PUT &name&i;

Chris

the value of the resolved macro variable

ChrisSelley — Fri, 07 Oct 2011 11:59:58 GMT

Hi again

sorry (forgot one myself)

PUT &&name&i;

Chris

the value of the resolved macro variable

DF — Fri, 07 Oct 2011 12:05:48 GMT

Hmm. It's strange - this only works for me when I use the triple ampersand as per my example. I wonder - is there differences in macro resolution between versions (I'm using 9.1.3)? That or I'm missing something!!

the value of the resolved macro variable

ChrisSelley — Fri, 07 Oct 2011 12:17:15 GMT

I'm using 9.1.3 I just used

%let i=2;

%let name2=acct_num;

data x;

acct_num=12345;

put &&name&i;

run;

the value of the resolved macro variable

art297 — Fri, 07 Oct 2011 12:23:21 GMT

%let i=2;

%let name2=acct_num;

data x;

acct_num=12345;

put &&name&i;

run;

resolves correctly on 9.3 as well. As woud two or more ampersands in this case.

the value of the resolved macro variable

DF — Fri, 07 Oct 2011 12:26:35 GMT

I just tried your code Chris and it works as you said.

The difference to mine is that I included a . after the macro names. When I add the same to your example I get an error, whereas it works with the extra ampersand.

Curious... I didn't expect that.

the value of the resolved macro variable

art297 — Fri, 07 Oct 2011 12:33:53 GMT

I wouldn't think that the period has any adverse effect. It doesn't on 9.3. Each of the following produces the same (desired) result:

%let i=2;

%let name2=acct_num;

data x;

acct_num=12345;

put &&name&i.;

run;

data x;

acct_num=12345;

put &&&name&i.;

run;

data x;

acct_num=12345;

put &&&&name&i.;

run;

the value of the resolved macro variable

DF — Fri, 07 Oct 2011 12:58:28 GMT

Ah, I see it now. My example decodes a further macro variable. I suppose we've understood the ops question slightly differently :).

the value of the resolved macro variable

art297 — Fri, 07 Oct 2011 13:05:49 GMT

No, actually, you were right! I was always taught that it NEVER hurts to ALWAYS end one's macro variables with a period. Obviously, there are some exceptions to that rule:

NONE of the following will work:

%let i=2;

%let name2=acct_num;

data x;

acct_num=12345;

put &&name.&i.;

run;

data x;

acct_num=12345;

put &&&name.&i.;

run;

data x;

acct_num=12345;

put &&&&name.&i.;

run;

the value of the resolved macro variable

Tom — Fri, 07 Oct 2011 18:16:38 GMT

You did not define a macro variable named NAME. So &name. will generate an error.

You can check how the &&'s are being combined by turning on SYMBOLGEN.

64 %let i=2;

65 %let name2=acct_num;

66 %let name=name;

72 %put 4-> &&&&name&i;

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable I resolves to 2

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable NAME2 resolves to acct_num

4-> acct_num

82 %put 4-> &&&&name.&i;

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable I resolves to 2

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable NAME resolves to name

4-> name2

the value of the resolved macro variable

art297 — Fri, 07 Oct 2011 18:32:39 GMT

Tom, You've ALMOST regained my faith in what I was taught, but there is still a discrepany I'd like someone to explain:

%let i=2;

%let name2=acct_num;

%let name=name;

/* All three of the following work */

data x;

acct_num=12345;

put &&name&i.;

run;

data x;

acct_num=12345;

put &&&name&i.;

run;

data x;

acct_num=12345;

put &&&&name&i.;

run;

/* However, below, only the 3 ampersand macro variable resolveds correctly*/

data x;

acct_num=12345;

put &&name&i.;

run;

data x;

acct_num=12345;

put &&&name&i.;

run;

data x;

acct_num=12345;

put &&&&name&i.;

run;

the value of the resolved macro variable

Tom — Fri, 07 Oct 2011 19:12:24 GMT

Art -

The period changes which pass will actually attempt to evaluate the macro variable value.

So in examples below using 2,3 and 4 leading &'s you see the effect in the symbolgen logic.

For 2 we have &&name.&i first tranlating into &name.2 which then translate into <value of &name>2.

But for 3 we have &&&name.&i first translating in &<value of &name>2. So when we set name=name we get &name2 and so the value of name2.

-Tom

80 %put 2-> &&name.&i;

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable I resolves to 2

SYMBOLGEN: Macro variable NAME resolves to name

2-> name2

81 %put 3-> &&&name.&i;

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable NAME resolves to name

SYMBOLGEN: Macro variable I resolves to 2

SYMBOLGEN: Macro variable NAME2 resolves to acct_num

3-> acct_num

82 %put 4-> &&&&name.&i;

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable I resolves to 2

SYMBOLGEN: && resolves to &.

SYMBOLGEN: Macro variable NAME resolves to name

4-> name2

the value of the resolved macro variable

gfarkas — Sat, 03 Dec 2011 02:18:41 GMT

Am I missing something? Those two sets of 3 data steps look the same to me.

the value of the resolved macro variable

art297 — Sat, 03 Dec 2011 04:59:08 GMT

They differ by the number of ampersands preceding the macro variable.

the value of the resolved macro variable

gfarkas — Sat, 03 Dec 2011 13:33:10 GMT

Right, but among the 6 in your post, #1 is identical to #4, and #2 is identical to #5, and #3 is identical to #6.

the value of the resolved macro variable

Linlin — Sat, 03 Dec 2011 14:49:31 GMT

Agreed. they are the same to me too.

the value of the resolved macro variable

Ksharp — Mon, 05 Dec 2011 06:27:27 GMT

remove double quote.

put &&name&i. ;