prxchange replace multiple matches

[AllanBowe]

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

[ed_sas_member]

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

[AllanBowe]

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)

[ed_sas_member]

No problem 

Could you please provide some representative sample data?

[AllanBowe]

done

[ed_sas_member · Accepted solution]

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,

[AllanBowe]

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.

[ed_sas_member]

You’re welcome 😊 !

[rafgag]

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?