topic Re: a question on %str() in SAS Programming

a question on %str()

stataq — Tue, 29 Oct 2024 15:20:23 GMT

Hello,

I have silly question: what does following code try to get?

%scan (&_indata,1,%str( %())

it looks like it try to get the 1st segment of &_indata.. I feel confused on the part of "%str( %()". Could anyone interpretate that for me, especially the part with % and (.

Thanks.

Re: a question on %str()

yabwon — Tue, 29 Oct 2024 15:32:21 GMT

Maxim#1: Read the documentation

https://documentation.sas.com/doc/en/pgmsascdc/9.4_3.5/mcrolref/p0pnc7p9n4h6g5n16g6js048nhfl.htm

Bart

Re: a question on %str()

ballardw — Tue, 29 Oct 2024 15:40:12 GMT

The third position of the scan and %scan is the list of characters used as delimiters. So someone wanted to set the list characters to include the % sign as well as space and the parentheses as delimiters. Because the macro language uses % as a special character they needed to use the %str() to prevent using that % in the list as a macro trigger.

By default %scan would use any of the following as delimiters:blank ! $ % & ( ) * + , - . / ; < ^¦

So one suspects that one or more of those characters were expected to appear in the values and they did not want those others to be treated as delimiters.

Re: a question on %str()

Kurt_Bremser — Tue, 29 Oct 2024 15:40:17 GMT

#STR is used for masking characters which would otherwise be discarded (the blank) or have special meaning in macro language.
Since the opening parenthesis is also needed as a delimiter for %SCAN, it is also put in as an argument for %STR. But the function would treat the two consecutive opening/closing brackets as a pair, which is not wanted; therefore the bracket is masked with % to prevent this. You can find this in https://documentation.sas.com/doc/de/pgmsascdc/9.4_3.5/mcrolref/n09tblrxldh8k0n1kt6dkj3xlxug.htm (the documentation of %STR).

Re: a question on %str()

Tom — Tue, 29 Oct 2024 15:49:57 GMT

It extracts the dataset name from a macro variable that might hold a dataset name with dataset options.

Example:

%let inds=sashelp.class(drop=age);
%let ds_only = %scan(&inds,1,%str( %());

Results

1    %let inds=sashelp.class(drop=age);
2    %let ds_only = %scan(&inds,1,%str( %());
3    %let libname = %upcase(%scan(work.&ds_only,-2,.));
4    %let memname = %upcase(%scan(&ds_only,-1,.));
5    %put &=inds &=ds_only &=libname &=memname;
INDS=sashelp.class(drop=age) DS_ONLY=sashelp.class LIBNAME=SASHELP MEMNAME=CLASS
6
7    %let inds=class;
8    %let ds_only = %scan(&inds,1,%str( %());
9    %let libname = %upcase(%scan(work.&ds_only,-2,.));
10   %let memname = %upcase(%scan(&ds_only,-1,.));
11   %put &=inds &=ds_only &=libname &=memname;
INDS=class DS_ONLY=class LIBNAME=WORK MEMNAME=CLASS