^ Is that comment necessary? Lana was written out of the show two seasons ago when Kristen Kruek left.
To be clear, did she left because she was written out or was she written out, because she left the show?
God knows why she she left as a principle, but then she came back for a three episode story arc the following season after Clark and Lois started inching toward each other, which made nearly absolutely no sense as she was stealing super powers from a mad clone of Lex Luthor. We thought, "hey cool, now Clark can't dent her pelvis" but her powers quickly became Kryptonite based and her presence was completely toxic to him now literally rather than just figuratively.
Oddly she sat out on Zod's occupation. Even after we saw a year into the future where the Kryptonians won and held the earth where the only thing that stood against them was Green Arrow and Chloe.