compare variables and notify when they are different from each other

[Alexxxxxxx]

Dear all,

how can I compare new_variable with the old_variable and show whether they have been changed( create a notification variable, say '1' if the new_variable is different from the old_variable, say '0' if both variables are the same.) The variables are different when they are the same word but different case.

for example, I expect to get the following result,

old_variable new_variable notification

apple Apple 1

juice juice 0

Original Original 0

mango nango 1

data have;
length 
old_variable $20 
new_variable $20 ;
input 
old_variable 
new_variable ;
cards;
apple Apple
juice juice 
Original Original 
mango nango 
;
run;

Could you please give me some suggestions about this?

thanks in advance

[Patrick · Accepted solution]

A simple comparison between the variables should do.

data have;
  length 
    old_variable $20 
    new_variable $20;
  input 
    old_variable 
    new_variable;

  change_flag= (old_variable ne new_variable);
  cards;
apple Apple
juice juice 
Original Original 
mango nango 
;
run;

What below line does:

change_flag= (old_variable ne new_variable);

old_variable ne new_variable -

Expression to compare the content in the two variables. The expression returns 1 (TRUE) if there is a difference and 0 (FALSE) if there is no difference

change_flag=

Variable to assign the result to from the result of the expression to the right of the equal sign.