Replace string with another string

[srinath3111]

data ds;
infile datalines;
input var1 var2$10.;
datalines;
201 Pakistan
206 Bangladesh
209 Russia
208 China

245 In

862 L
;
run;

what i need is

Paxxstan
baxxladesh
Ruxxia

chxxa

In
L

[PaigeMiller]

data want;
    set have;
    substr(country,3,1)='x';
    substr(country,4,1)='x';
run;

[Astounding]

One case that is missing from your example:  Sri

Should that become Srx or should it become Srxx?

At any rate, here are the basic tools that you can modify if needed:

if length(var2) > 2 then substr(var2, 3, 2) = 'xx';

[soham_sas]

data want;
set ds;
if length(var2) >2 then
var3 = tranwrd(var2,substr(var2,3,2),"XX");
else var3 = var2;
run;

[SuryaKiran]

You can use substr() function along with IF condition:

data want;
set ds;
if length(var2)<=2 then new_var=var2;
else if length(var2)=3 then new_var=substr(var2,1,2)||"x"||substr(var2,5);
else new_var=substr(var2,1,2)||"xx"||substr(var2,5);
run;

Another alternate solution will be using the Perl expression:

data want;
set ds;
new_var=substr(var2,1,2)||prxchange('s/[a-z][a-z]/xx/i',1,substr(var2,3));
run;