What is the closest function to R's nlminb in Python?
nlminb is an unconstrained and bounds-constrained quasi-Newton method optimizer. This code is based on a FORTRAN PORT library by David Gay in the Bell Labs. As for Pyhon quasi-Newton menthods are:

Unconstrained minimization
Method BFGS uses the quasi-Newton method of Broyden, Fletcher, Goldfarb, > > and Shanno (BFGS) [5] pp. 136. 
Bound-Constrained minimization
Method L-BFGS-B uses the L-BFGS-B algorithm [6], [7] for bound
  constrained minimization.

L-BFGS-B  & BFGS, being a member of quasi-Newton family methods, are the closest analogs of nlminb.
Python scipy.optimize.minimize function supports the following methods:

Nelder-Mead
Powell
CG
BFGS
Newton-CG
L-BFGS-B  
TNC
COBYLA
SLSQP
trust-constr
dogleg
trust-ncg
trust-exact
trust-krylov

Which method is closest to R's nlminb?