if statement conditions are embedded in a column

Data can not modify the statements of a running DATA Step.

There is no 'dynamic expression resolver' that is part of data step.

There are some options though

• Use the data to write source code
  • A different conditional has to be performed for each row (n)
• Use resolve() to dynamically evaluate an expression in the macro system.
  • The values of the variables have to be replaced into the conditional for each row (n)

Write a program

filename evals temp;

data _null_;
  file evals;
  set test;

  length statement $256;

  put 'if _n_ = ' _n_ ' then do;';

  if missing(condition1) then 
    statement = 'flag="X";'; /* 'call missing(flag);'; */
  else
    statement = 'flag = ifc(' 
    || trim(condition1) || ',' 
    || quote(trim(value_cond1_true )) || ','
    || quote(trim(value_cond1_false ))
    || ');';

  put statement;
  put 'end;';
run;

options source2;

data want;
  set test;
  length flag $8;
  %include evals;
  keep x1 x2 flag;
run;

filename evals;

RESOLVE function

data want;
  set test;

  length flag $8 cond expr $256;

  cond = condition1;
  cond = transtrn(cond,'x1',cats(x1));
  cond = transtrn(cond,'x2',cats(x2));

  expr = 'ifc(' || trim(cond) || ',' || 
           trim(value_cond1_true) || ',' || 
           trim(value_cond1_false) ||
         ')';

  if not missing (condition1) then 
    flag = resolve ('%sysfunc(' || trim(expr) || ')');
  else
    flag = "X";

  keep x1 x2 flag;
run;