topic Re: Need help on PRXCHANGE function in SAS Procedures

Need help on PRXCHANGE function

GPatel — Tue, 21 Jul 2015 18:01:58 GMT

I have following SAS Code, and need help with PRXCHANGE function.

Output of SAS code below is attached in an Excel file.

Data A ;

Set MisMatch;

IF Index(DrugName,'MG') > 0 then do;

var2=prxchange("s/[^0-9]//",-1,Drug_Strength);

var3=prxchange("s/[^A-Z]//",-1,Drug_Strength);

end;

run;

See the records (in Excel file) # 65,68-70,72-77,87-89. How can I get correct results using PRXCHANGE function?

The goal is to match Drug_Strength in a Drugname string.

If there is a better way, please let me know.

Regards,

Girish Patel

Re: Need help on PRXCHANGE function

PhilC — Tue, 21 Jul 2015 19:03:46 GMT

Hi, I don't think PRXCHANGE is the perfect match for what you are doing. I think you want to identify the place in the string that the characters begin to be alphabetic, which signifies the beginning character position of the units. PRXMATCH will help you start. SUBSTR gets you the rest of the way. Of course this fails us when Drug_Strength becomes something like "5MG-1000MG"

libname user "C:\MisMatch_C_07212015.xls";

Data L ;
if _N_ = 1 then do;
      retain PerlExpression;
      pattern = "/[A-Z]/";
      PerlExpression = prxparse(pattern);
end;

Set 'result#srx$'n (drop=var2 var3);

length var2 var3 $ 32;
IF Index(DrugName,'MG') > 0 then do;
    start = prxmatch(PerlExpression, Drug_Strength);
    if start>0 then do;
      var2=compress(substr(Drug_Strength,1,start-1));
      var3=compress(substr(Drug_Strength,start,32));
    end;
end;
run;

Re: Need help on PRXCHANGE function

slchen — Tue, 21 Jul 2015 20:01:57 GMT

data want;

set string;

IF Index(DrugName,'MG') > 0 then do;

_var2=prxchange('s/[^0-9-.]//i',-1,drug_strength);

_var3=prxchange('s/[^a-z\/]//i',-1,drug_strength);

end;

run;