Need help creating a new variable using existing variable...

[RazzleBayker]

code Hi guys,

I was wondering if anyone knew how to create a new variable by performing a simple mathematical operation on an existing column.

I've shown the operation im trying to do in the NEW COLUMN):

EXISTING COLUMN                        NEW COLUMN       

          -1                   

          -5                                                   (-5) - (-1)

           7                                                   ( 7) - (-5)   

          -3                                                   (-3) - ( 7)  

           2                                                       etc...

           9                            

           4                             

           1   

I basically need to create a new column that subtracts existing observation #1 from #2, existing observation #2 from #3, and so on...

Any ideas as to how I can write a code for this?

Thanks in advance.

[Linlin]

data want;

  set your_dataset;

new=EXISTING_ COLUMN-lag(EXISTING_ COLUMN);

run;

[Astounding]

Also note ... we use LAG quite often, so often that we might forget about:

data want;

   set your_dataset;

   new_column = dif(EXISTING_COLUMN);

run;

[Linlin]

That is so true. Thank you! - Linlin

[RazzleBayker]

Thank you guys so much, I appreciate the help.