problem modifying a dataset array

Hi all,

when i try the code below, i get these errors :

------------------------ERRORS------------------------

Error using dataset/subsasgnParens (line 202) Right hand side must be a dataset array.

Error in dataset/subsasgn (line 79) a = subsasgnParens(a,s,b,creating);

Error in Alex_2 (line 23) COMP(COMP.DY < p1,:) = p1;

-------------------------CODE-------------------------

for x=1 [u,l]=funcf(x) end

p1 = prctile(COMP.DY, [u]) p2 = prctile(COMP.DY, [l])

COMP(COMP.DY < p1,:) = [p1]; COMP(COMP.DY > p2,:) = [p2];

I just want to modify the data in an array if it respects the above condition.

Does anyone have an idea of what i got wrong here please ?

Thanks :) !