sort last N letters

[pavank]

data sorted_string;
    length Str $50 ;
    Str = "ASDFKBSDEFWKSR";
run;

Sorting last N letters in str  variable

[PeterClemmensen]

How long can str be and how large can N be?

[pavank]

HI PeterClemmensen,

suppose last 5 letters 

[PeterClemmensen · Accepted solution]

Here is an easy to follow approach

data want;
   set sorted_string;

   array a {100} $ _temporary_;

   N = 5;
   pos = max(1, length(str)-(N - 1));
   
   sub = substrn(str, pos, N);

   do i = 1 to length(sub);
      a[i] = char(sub, i);
   end;

   call sortc(of a[*]);

   substr(str, max(1, pos, N)) = cats(of a[*]);

run;

[PaigeMiller]

Here's one way for N=5

data intermediate;
    set sorted_string;
    array letter $ letter1-letter5 _temporary_;
    last5letters=substr(str,length(str)-4);
    do i=1 to 5;
        letter(i)=substr(last5letters,i,1);
    end;
    call sortc(of letter:);
    last5letters_sorted=cats(of letter:);
    sorted_string=cats(substr(str,1,length(str)-5),last5letters_sorted);
    drop i;
run;

For general N, you could replace 5 with a macro variable.

[pavank]

Hi PaigeMiller 

Thank you very much your solution