rpy2 问题，从 Python 传递 list() 作为参数给 R

Question

我正在尝试使用rpy2从numpy数组拟合一个非线性曲线，但遇到了困难，因为我不知道如何在R那边传递'start'参数。我使用的是R 2.12.1和Python 2.6.6。

Error in function (formula, data = parent.frame(), start, control = nls.control(),  : 
parameters without starting value in 'data': responsev, predictorv
Traceback (most recent call last):
File "./employmentsHoro.py", line 279, in <module>
nls.nls2(formula=formula, data=dataf, start=mylist)
File "/usr/lib/python2.6/dist-packages/rpy2/robjects/functions.py", line 83, in __call__
return super(SignatureTranslatedFunction, self).__call__(*args, **kwargs)
File "/usr/lib/python2.6/dist-packages/rpy2/robjects/functions.py", line 35, in __call__
res = super(Function, self).__call__(*new_args, **new_kwargs)
rpy2.rinterface.RRuntimeError: Error in function (formula, data = parent.frame(),start, control = nls.control(),  : 
parameters without starting value in 'data': responsev, predictorv

有没有人能帮我弄清楚如何将一个list()对象传递给nls公式？

我代码中相关的部分是：

import rpy2.robjects as robjects
from rpy2.robjects import DataFrame, Formula
import rpy2.robjects.numpy2ri as npr
import numpy as np
from rpy2.robjects.packages import importr
nls = importr('nls2')
stats = importr('stats')

mylist = robjects.r('list(a=700,b=0.8,c=200000)')

dataf = DataFrame({'responsev': professions, 'predictorv': totalEmployment})
starter= DataFrame({'a':700,'b':0.80,'c':200000})
formula = Formula('responsev ~I( a*(predictorv/c)^b )/( 1+( predictorv/c )^b )')
nls.nls2(formula=formula, data=dataf, start=starter)

Answer 1

主要的错误是这个：

Error in function (formula, data = parent.frame(), start, control = 
nls.control(),  : parameters without starting value in 
    'data': responsev, predictorv

变量 professions 和 DataEmployment 是在哪里声明的呢？它们似乎没有初始值，可能你需要把它们改成 R 能理解的某种形式？