change variable values

[skargae]

Hi, 

I have a variable "gestational_age" in the data set decoded as, for example, "32+2 weeks". How can I easily convert it to a numeric variable and add the first number to the second one , turning the value into "34" instead of 32+2?

Thanks a lot in advance! 

[Tom]

Not sure about easy, but for such simple arithmetic you could use the RESOLVE() function to take advantage of the power of the macro processing language.

data test;
  gestational_age = "32+2 weeks" ;
  expression=scan(gestational_age,1,' ');
  age = input(resolve(cats('%sysevalf(',expression,')')),32.);
run;

proc print;
run;

       gestational_
Obs        age         expression    age

 1      32+2 weeks        32+2        34