topic Re: Replace a text string when it occurs more than once in SAS Programming

Replace a text string when it occurs more than once

Valentin_HU — Wed, 04 May 2011 16:15:51 GMT

Dear all,

I have the following problem:
I use the macro described here: http://www2.sas.com/proceedings/sugi24/Coders/p086-24.pdf.

Code:
%macro replace (dataset = , chkvar = , search = , replace =,
newvar = );
data &dataset (drop = textpos) newvars;
length &newvar $ 200;
set &dataset;
textpos = index(upcase(&chkvar), upcase("&search"));
oldvar = &chkvar;
if textpos ne 0 then
do;
if textpos ne 1 then
&newvar = substr(&chkvar, 1, (textpos - 1)) ||"&replace"||substr(&chkvar, (textpos+length("&search")));
else &newvar = "&replace"||
substr(&chkvar, (textpos + length("&search")));
output newvars;
end;
else &newvar = &chkvar;
output &dataset;
run;
proc print data = newvars;
title “SEARCH FOR ‘&search’ AND REPLACE WITH ‘&replace’”;
var oldvar &newvar;
run;
%mend replace;

This macro replaces a specified string in a cell. The problem is, that it only replaces the first specified string that appears in a cell, when the specified string occurs more than once, the macro does not replace all specified string appearing in the cell but only the first one. How could the macro be fixed in order to replace the specified string as often as the specified string occurs in the cell?

Thanks a lot for your help.

Valentin

Re: Replace a text string when it occurs more than once

SPR — Wed, 04 May 2011 18:12:15 GMT

Hello Valentin,

One of the possible solutions is to loop of this macro making a slight change in its code, namely output testpos as a macro variable, and loop untill testpos=0 like this:
[pre]
%macro replace (dataset = , chkvar = , search = , replace =,
newvar = );
%global tp;
data &dataset (drop = textpos) newvars;
length &newvar $ 200;
set &dataset;
textpos = index(upcase(&chkvar), upcase("&search"));
CALL SYMPUTX('tp',textpos);
oldvar = &chkvar;
if textpos ne 0 then
do;
if textpos ne 1 then
&newvar = substr(&chkvar, 1, (textpos - 1)) ||"&replace"||substr(&chkvar, (textpos+length("&search")));
else &newvar = "&replace"||
substr(&chkvar, (textpos + length("&search")));
output newvars;
end;
else &newvar = &chkvar;
output &dataset;
run;
proc print data = newvars;
title “SEARCH FOR ‘&search’ AND REPLACE WITH ‘&replace’”;
var oldvar &newvar;
run;
%mend replace;
%macro a;
%global tp;
%do %until (&tp = 0);
%replace (dataset = a, chkvar = a, search = dg, replace = yy, newvar =a );
%end;
%mend a;
data a;
a="asdgdfgdg";
b="dg";
run;
%a
[/pre]
Sincerely,
SPR

Re: Replace a text string when it occurs more than once

polingjw — Wed, 04 May 2011 19:29:41 GMT

Maybe I’ve misunderstood your objective, but wouldn’t it be a lot easier to just use the TRANWRD function?

Re: Replace a text string when it occurs more than once

chang_y_chung_hotmail_com — Wed, 04 May 2011 21:37:52 GMT

Here is one way. hth.

/* test data */
data one;
   old = "asdgdfgdg";
run;

/* create a new var replacing dg with YY in old */
data two;
   set one;
   length new $9;
   new = prxchange("s|dg|YY|", -1, old);
run;

/* check */
proc print data=two;
run;
/* on lst
   Obs   old          new
   1     asdgdfgdg    asYYdfgYY
*/

Re: Replace a text string when it occurs more than once

art297 — Wed, 04 May 2011 22:07:57 GMT

I like Chang's suggested code and, if you want, it would be simple to wrap it in a macro. E.g., the following uses the same structure (mostly) of the original:
[pre]
%macro replace (dataset = , search = , replace =, variable =, newlength = );
data &dataset. (drop = oldvar);
set &dataset. (rename=(&variable.=oldvar));
length &variable $&newlength.;
&variable. = prxchange("s|&search.|&replace.|", -1, oldvar);
run;
%mend replace;
data have;
informat aetext $50.;
input PTID AETEXT &;
cards;
110 ABD. CRAMPING
160 INTRA-ABD. ABSCESS ABD.
190 (L) ABD. PAIN
220 FOOT ULCER (L) FOOT
230 ABD. PAIN
360 (L) ELBOW CONTUSION
440 PAIN (L) KNEE
520 ACNE
520 TINGLING (L) FOOT
530 ASCITES ABD.
;
run;

%replace (dataset = have,
search = ABD.,
replace = ABDOMINAL,
variable = aetext,
newlength = 50)
[/pre]
HTH,
Art

> Here is one way. hth.

>

>
> style="color:#008000;font-family:Courier
> New;font-size:10pt;">/* test data */ > pan>

>
> style="color:#000080;font-family:Courier
> New;font-size:10pt;">data
> style="font-family:Courier
> New;font-size:10pt;"> one;

>      old
> =
> style="color:#800080;font-family:Courier
> New;font-size:10pt;">"asdgdfgdg"
> style="font-family:Courier
> New;font-size:10pt;">;

>
> style="color:#000080;font-family:Courier
> New;font-size:10pt;">run
> style="font-family:Courier
> New;font-size:10pt;">;

>

>
> style="color:#008000;font-family:Courier
> New;font-size:10pt;">/* create a new&nb
> sp;var replacing dg with YY i
> n old */

>
> style="color:#000080;font-family:Courier
> New;font-size:10pt;">data
> style="font-family:Courier
> New;font-size:10pt;"> two;

>       > pan>set
> style="font-family:Courier
> New;font-size:10pt;"> one;

>       > pan>length
> style="font-family:Courier
> New;font-size:10pt;"> new $
> style="color:#008080;font-family:Courier
> New;font-size:10pt;">9
> style="font-family:Courier
> New;font-size:10pt;">;

>      new
> = prxchange(
> style="color:#800080;font-family:Courier
> New;font-size:10pt;">"s|dg|YY|"
> style="font-family:Courier
> New;font-size:10pt;">, -
> style="color:#008080;font-family:Courier
> New;font-size:10pt;">1
> style="font-family:Courier
> New;font-size:10pt;">, old);

>
> style="color:#000080;font-family:Courier
> New;font-size:10pt;">run
> style="font-family:Courier
> New;font-size:10pt;">;

>

>
> style="color:#008000;font-family:Courier
> New;font-size:10pt;">/* check */

> />
>
> style="color:#000080;font-family:Courier
> New;font-size:10pt;">proc
> style="font-family:Courier
> New;font-size:10pt;">
> style="color:#000080;font-family:Courier
> New;font-size:10pt;">print
> style="font-family:Courier
> New;font-size:10pt;">
> style="color:#0000FF;font-family:Courier
> New;font-size:10pt;">data
> style="font-family:Courier
> New;font-size:10pt;">=two;

>
> style="color:#000080;font-family:Courier
> New;font-size:10pt;">run
> style="font-family:Courier
> New;font-size:10pt;">;

>
> style="color:#008000;font-family:Courier
> New;font-size:10pt;">/* on lst

> />
>    Obs
>      old   &nb
> sp;      new

> />
>     1 &n
> bsp;   asdgdfgdg
> ;asYYdfgYY

>    */