topic Re: How to copy one macro variable data to another macro variable in New SAS User

How to copy one macro variable data to another macro variable

bhanuprakash — Wed, 31 Oct 2018 06:20:55 GMT

By using the below I am passing one macro variable. It has multiple words. Based on number of words loop will execute and each time one word should be resolved and that should be the macro variable.

Please see the below codes and let me know why second one is not working.

* Working ;

%macro test(var_names=) ;
%do i = 1 %to %sysfunc(countw(&var_names.)) ;
%put "&i." ;
var_main = scan(&var_names.,&i.) ; output ;
%end ;
%mend test ;

data testing ;
%test(var_names = %str("bhanu prakash")) ;
run ;

* Not working ;

%macro test(var_names=) ;
%do i = 1 %to %sysfunc(countw(&var_names.)) ;
%put "&i." ;
%let var_main = %scan(&var_names.,&i.) ;
%put &var_main. ;
%end ;
%mend test ;

data testing ;
%test(var_names = %str("bhanu prakash")) ;
run ;

Re: How to copy one macro variable data to another macro variable

Kurt_Bremser — Wed, 31 Oct 2018 06:56:13 GMT

@bhanuprakash wrote:

By using the below I am passing one macro variable. It has multiple words. Based on number of words loop will execute and each time one word should be resolved and that should be the macro variable.

Please see the below codes and let me know why second one is not working.

* Working ;

%macro test(var_names=) ;
%do i = 1 %to %sysfunc(countw(&var_names.)) ;
%put "&i." ;
var_main = scan(&var_names.,&i.) ; output ;
%end ;
%mend test ;

data testing ;
%test(var_names = %str("bhanu prakash")) ;
run ;

* Not working ;

%macro test(var_names=) ;
%do i = 1 %to %sysfunc(countw(&var_names.)) ;
%put "&i." ;
%let var_main = %scan(&var_names.,&i.) ;
%put &var_main. ;
%end ;
%mend test ;

data testing ;
%test(var_names = %str("bhanu prakash")) ;
run ;

Maxim 1: read the documentation, in this case of the %put macro statement.

All it does is write text to the log; if &var_main is not already present in the global symbol table, it will be local to the macro, and its contents lost when the macro stops executing.

The first macro is actually creating something, namely the code that writes observations to the dataset. The second macro creates nothing, so you end up with this data step code:

data testing ;
run ;

Re: How to copy one macro variable data to another macro variable

bhanuprakash — Wed, 31 Oct 2018 07:23:21 GMT

Hi KurtBremser,

Thank you so much for the reply.

I don't have any issue with put statement or data step.

It is the issue with scan function. when I used scan function in %let statement then that is not working.

I would like to know the reason why that is not working or am I missing anything.

Thanks & Regards,

Bhanuprakash Pala

Re: How to copy one macro variable data to another macro variable

Kurt_Bremser — Wed, 31 Oct 2018 07:40:36 GMT

Maxim 2: read the log. In this context, "read" also means "understand and interpret".

37         data testing ;
38         %test(var_names = %str("bhanu prakash")) ;
"1"
ERROR: Literal contains unmatched quote.
ERROR: The macro TEST will stop executing.
39         run ;

Keep in mind that the macro preprocessor is a pure text processor; everything is text to it, including quotes(!).

%scan dissects the string with the masked quotes at the blank, and so you get

"bhanu

as the first result, which is a literal with an unmatched quote.

Text strings in macros need no quotes, try this:

%macro test(var_names=) ;
%do i = 1 %to %sysfunc(countw(&var_names.)) ;
%put "&i." ;
%let var_main = %scan(&var_names.,&i.) ;
%put &var_main. ;
%end ;
%mend test ;

%test(var_names = bhanu prakash) ;

Since the macro does not create any data step code, the data step itself is not needed.

Re: How to copy one macro variable data to another macro variable

bhanuprakash — Wed, 31 Oct 2018 08:24:23 GMT

Sorry for the silly question and Thank you so much for the brief explanation.

Re: How to copy one macro variable data to another macro variable

Kurt_Bremser — Wed, 31 Oct 2018 08:27:52 GMT

@bhanuprakash wrote:
Sorry for the silly question and Thank you so much for the brief explanation.

A question can't be silly if you learn something from it.