The trouble with Lag.

[Asender]

Hi all.

Can anyone explain why the does not work :

data AS.DATE_FILL;
set AS.SORTHIST;
by POLICY;
if not first.POLICY then
do;
if date6 = . then date6 = lag(date6);
end;
if date6 = . then delete;
if date3 = . then delete;
run;

And this does :

data AS.DATE_FILL;
set AS.SORTHIST;
by POLICY;
held_date6 = lag(date6);
if not first.POLICY then
do;
if date6 = . then date6 = held_date6;
end;
if date6 = . then delete;
if date3 = . then delete;
run;

Thanks.

 

[klaz2002]

Lag doesn't work correctly in a loop. (if, else and last but not least do's and ends)

Why not use the retain statement?
Klaz