Hi everybody,

My pb is the following.

I have n processes in my table, indexed by T (n*T rows).

The state of each process (Raph) is indicated by the variable 'state'.

I want to create a variable movement 'mvt' : each time a raph goes from one value of state to another value of state, i want mvt to be oldstate_newstate.

I tried to do this in a data step using RETAIN and LAG. But it does not work properly.

Here's my programm :

DATA roue.fort; retain raph state; set data; length mvt $12; if state=lag(state) then mvt=0; else if raph=lag(raph) then mvt=compress(lag(state)||"_"||state); run;

The result is that mvt appears to be different from zero at the relevent times, but i get :

mvt=newstate_newstate instead of oldstate_newstate.

It can be done in 2 datasteps, but I would be ashamed to do so...

Any help would be very appreciated.

Philippe.

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