topic Re: macro resolving issue in SAS Programming

macro resolving issue

Kethy — Sun, 30 Jun 2013 17:48:24 GMT

Can someone please help me in understanding the resolving of values for ''a" in below case?

I know like for &a is usa, but the rest are quite confusing with the output that i see in sas log and the way how i understood conceptually.

Much help is appreciated if someone can explain me as to how SAS interprets here.

%let a=usa;

%let usa=america;

%let america=states;

%put &a &&a &&&a &&&&a &&&&&a &&&&&&a;

Re: macro resolving issue

umashankersaini — Sun, 30 Jun 2013 19:18:34 GMT

Hi,

We can use any number of ampersands (&) in an indirect macro variable reference.

It resolves the entire reference from left to right. if a pair of ampersands (&&) is encountered, the pair is resolved to single ampersand, then the next part of the reference is processed.

%put &a; * usa *;

%put &&a; * usa *;

%put &&&a; * America * ;

explaination : && resolves to single & (put in reserve) resolve &a to usa, now with reserve & sas reads &usa , result is america.

%put &&&&a; * usa . pairing && and && comes to && resolves to & *;

explaination : && resolves to single & (put in reserve) again && resolve to single & (put in reserve) , now we have only a, no execution. in reserve we have && which is &a. again result is usa.

%put &&&&&a;

explaination : && resolves to single & (put in reserve) again && resolve to single & (put in reserve), now we have &a , resolve to usa. In reserve we have two ampersand, which is one (&) and now it is &usa, resolve to America.

%put &&&&&&a;

explaination : && resloves to single & (put in reserve) again && resolve to single & (put in reserve) , && resolve to single & (put in reserve), now we have only a , no execution. In reserve we have &&& so again result is America.

%put &&&&&&&a .... would resolve to state, because we would have three ampersand (in reserve) and &a resolve to usa. &&&usa resolve to &america and it would resolve to States.

Sorry as i have put my explanation in a lay man manner, if i hurt someone , apologies......

Regards

Uma Shanker Saini

Re: macro resolving issue

Tom — Mon, 01 Jul 2013 01:48:53 GMT

That's a perfect answer.

Re: macro resolving issue

NishunkSaxena — Mon, 01 Jul 2013 06:38:22 GMT

Marvellous answer buddy.............

Re: macro resolving issue

Kethy — Mon, 01 Jul 2013 15:53:26 GMT

Awesome explanation.Thank you Uma Shanker Saini.

Re: macro resolving issue

umashankersaini — Wed, 03 Jul 2013 17:21:40 GMT

Tom, Nishunk and Kethy : Thank you so much for warm appreciation....