Array linear interpolation

[FriedEgg]

More simply with SAS/ETS you could simply have, since the id variable is already id and we want to expand all the other variables:

/*modify 0's to missing and expand*/

data foo;

set foo;

array v[7];

do _n_=1 to 7;

if v[_n_]=0 then call missing(v[_n_]);

end;

proc expand;

run;