Help to understand a few SAS symbols

[Mirisage]

Hi SAS Forum,

This code was written by another programmer.

I am trying to understand two symbols highlighted in yellow color in it.

%if &income = 0 %then %do;

       data wave_2;

         set wave_1;

         by transit_branch acctnumber;

         if ~(first.acctnum and last.acctnum) then do;

           if currbal ~= (acctbal * -1) then delete;

         end;

         run;

%end;

%else %do;

    proc sort data=wave_1 out=wave_2 nodupkey;

         by transit_branch acctnumber;

         run;

%end;

Q:

Could you please let me know if the way I understand it correct.

if ~(first.acctnum and last.acctnum) then do;

This means,

if not (first.acctnum and last.acctnum) then do;

if currbal ~= (acctbal * -1) then delete;

This would mean:

if currbal ne (acctbal * -1) then delete;

Thanks

Mirisage

[ArtC · Accepted solution]

Yes the ~ is another symbol for not.  In addition to the word 'not' you can also use the ^ symbol.  On the mainframe this symbol looks different but is still the shift-6 key.  Some languages use <> or >< for variations of not equal.  These two combinations have different meanings in SAS and IMO should be avoided.