how to assign the nth component of a Multifab to an Array4

[ztdepztdep]

I have define a Multifab F with 9 components, and I want to extract the nth components to an Array4. how to resolve this problem?

Array4 statein = F.const_array(mfi); ?

[WeiqunZhang]

auto statein = F.const_array(mfi,n);