topic Re: prxchange replace multiple matches in SAS Programming

prxchange replace multiple matches

AllanBowe — Thu, 05 Mar 2020 18:21:25 GMT

Can anyone help me with this little puzzle? I'm trying to use capture buffers to perform conditional replacement of multiple values in a single pass. The replaced values are two characters (versus the single character I'm matching) so I can't use translate. I could use multiple instances of tranwrd (or nest the prxchange), but I'm keen to know - is a single pass possible? I do not know the length or content of my input values.

data _null_;
  have=prxchange('s/a|g|f/$1aa$2gg$3ff/',-1,'sasgf');
  put have=;
  put 'want=saasggff';
run;

result:

 have=saaggffsaaggffaaggff
 want=saasggff

Edit - to clarify, the values on the right should be anything, eg:

 73         data _null_;
 74           have=prxchange('s/a|g|f/$1xx$2yy$3zz/',-1,'sasgf');
 75           put have=;
 76           put 'want=sxxsyyzz';
 77         run;
 
 have=sxxyyzzsxxyyzzxxyyzz
 want=sxxsyyzz

Re: prxchange replace multiple matches

ed_sas_member — Thu, 05 Mar 2020 18:15:28 GMT

Hi @AllanBowe

Does this answer your question?

data _null_;
  have=prxchange('s/(a|g|f)/$1$1/',-1,'sasgf');
  put have=;
  put 'want=saasggff';
run;

 71         data _null_;
 72           have=prxchange('s/(a|g|f)/$1$1/',-1,'sasgf');
 73           put have=;
 74           put 'want=saasggff';
 75         run;
 
 have=saasggff
 want=saasggff

Re: prxchange replace multiple matches

AllanBowe — Thu, 05 Mar 2020 18:22:06 GMT

thanks for the quick response! You solved the puzzle (as it was set) but I'm still stuck. The replacement values could be anything (I should have picked better examples)

Re: prxchange replace multiple matches

ed_sas_member — Thu, 05 Mar 2020 18:22:28 GMT

No problem

Could you please provide some representative sample data?

Re: prxchange replace multiple matches

AllanBowe — Thu, 05 Mar 2020 18:22:56 GMT

done

Re: prxchange replace multiple matches

ed_sas_member — Thu, 05 Mar 2020 18:53:48 GMT

Hi @AllanBowe

Here is an attempt to achieve this:

data ref;
	input match $ replace $;
	datalines;
a xx
g yy
f zz
;	

data _null_;
	set ref end=eof;
	length have $ 30;
	if _n_=1 then have = 'sasgf';
	retain have;
	have=prxchange(cats('s/',match,'/',replace,'/'),-1,have);
	if eof then do;
		put have=;
		put 'want=sxxsyyzz';
	end;
run;

My best,

Re: prxchange replace multiple matches

AllanBowe — Thu, 05 Mar 2020 18:55:35 GMT

ha ha - ok. From what I can tell, it is not possible to do what I am trying to do. But I admire the approach you took to avoid nesting the regex calls 🙂

accepted.

Re: prxchange replace multiple matches

ed_sas_member — Thu, 05 Mar 2020 18:59:59 GMT

You’re welcome 😊 !

Re: prxchange replace multiple matches

rafgag — Tue, 22 Dec 2020 13:51:13 GMT

Hi @AllanBowe,

Is this what you were looking for?

28 data _null_;

29 /* have=prxchange('s/a|g|f/$1aa$2gg$3ff/',-1,'sasgf');*/

30 /* put have=;*/

31 put 'want=saasggff';

32 have=prxchange('s/(a|g|f){1}?/$1$1/',-1,'sasgf');

33 put have=;

34 run;

want=saasggff

have=saasggff

36 data _null_;

37 /*have=prxchange('s/a|g|f/$1xx$2yy$3zz/',-1,'sasgf');*/

38 /*put have=;*/

39 put 'want=sxxsyyzz';

40 have=prxchange('s/([^agf]*)(a){1}?([^agf]*)(g){1}?([^agf]*)(f){1}?/$1xx$3yy$5zz/',-1,'sasgf');

41 put have=;

42 run;

want=sxxsyyzz

have=sxxsyyzz

The former prxchange works, but only if you want to duplicate specific characters in an input string.

But I guess that's not exactly what you were after... The latter prxchange should be closer to meet your requirements.

So the $64k question is: does it?