Question

I have a numpy 2D array self.sub
and i want to use it in rpy2 kmeans.
k = robjects.r.kmeans(self.sub,2,20)
i always get the following error:
valueError: nothing can be done for the type at the moment!
what can i do?

Answer 1

From the rpy2 docs, R matrices are just vectors with their dim attribute set. So for a numpy two-dimensional array x

import rpy2.robjects as robj

nr, nc = x.shape
xvec = robj.FloatVector(x.transpose().reshape((x.size))
xr = robj.r.matrix(xvec, nrow=nr, ncol=nc)

You have to transpose the numpy array because R fills matrices by columns.

Edit: Actually, you could just set byrow=True in the R matrix function, and then you wouldn’t need to transpose.