Your code produces the same average values as the the OPed code, but the error values differ: 0.193649167310365 versus 6.454972e-002 for the OPed code.

I'm not familiar with jackknife averages/errors (update: in fact, I don't even know if pyari_billi's code yields the correct error values), so I don't know if this is significant.

However, I certainly agree that the OPed code can be considerably simplified.