Subratrion the obseravtions in one variable

[R_Win]

Hi
i have a data set

data x;
input sal;
cards
10
9
8
7
6
run;
i want the output like this id should substract form the first obs-second obs

the output shud be like this

sal;
10
1
1
1
run;

[LinusH]

You could use the lag() function or the retain statement to make calculations between different observations.

/Linus