How to use SAS macro with %DO and %IF - sas

Question

When I ran a macro, the PassengerID_Class had a null value.
I think there is a problem with the sentence below.
%if PassengerID >= &&P&i and PassengerID < &&P&k %then PassengerID_Class = &i. ;
PassengerID is a column containing values from 1 to 891.
P1,P2,...,Pi are the quantiles.
Below is my code.
%macro do_loop;
DATA _NULL_;
SET PERCENTILES100_Transpose;
call symput("P"||left(_n_),Column1);
RUN;
Data Groups100;
Set sample;
%do i=2 %to 99;
%Let k = %eval(&i.+1);
%if PassengerID >= &&P&i and PassengerID < &&P&k %then PassengerID_Class = &i. ;
%end;
%mend;
%do_loop;

Answer 1

You cannot test the value of dataset variable with a macro expression. Just use the macro to generate a normal IF statement, the same as you are using the macro to generate the DATA and other SAS statements.
if &&P&i <= PassengerID < &&P&k then PassengerID_Class = &i. ;
But why use macro code at all? Just read the cutoff values into a temporary array.
data Groups100;
set sample;
array p[100] _temporary_;
if _n_=1 then do index=1 by 1 until(eof);
set PERCENTILES100_Transpose(keep=column1) end=eof;
p[index]=column1;
end;
PassengerID_Class=0;
do index=2 to 99 until(PassengerID_Class>0);
if p[index] <= PassengerID < p[index+1] then PassengerID_Class = index ;
end;
drop index column1 ;
run;
Note that using the data directly will also avoid loss of precision caused by converting the numbers into text strings to store macro variables.