How to convert numpy array to R matrix?

Question

How do you convert a numpy array to a R matrix using rpy2? This might be trivial, but I cannot find a good answer in the documentation. I can get this working by first converting to a pandas dataframe as an extra step, but this seems redundant.

Working example:

import numpy as np
from pandas import *
import pandas.rpy.common as com
import rpy2.robjects as ro

B=np.array([[1,2,3],[4,5,6],[7,8,9]])

Rmatrix = com.convert_to_r_matrix(B)  # Does not work

#Extra conversion via pandas dataframe
PandasDF = DataFrame(B)
Rmatrix = com.convert_to_r_matrix(PandasDF)
ro.r.assign("Bmatrix", Rmatrix)
print(ro.r["Bmatrix"])

Does [this post](http://stackoverflow.com/a/10037302/489704) help? — jbaums, Dec 04 '14 at 00:48
Yes, that works, but I also found this which is even more to the point: [converting python objects for rpy2](http://stackoverflow.com/questions/2447454/converting-python-objects-for-rpy2) @jbaums — fileunderwater, Dec 04 '14 at 20:02

score 6 · Answer 1 · edited May 23 '17 at 12:16

6

This works, based on the post Converting python objects for rpy2 and the rpy2 documentation on numpy to rpy2 conversion:

import rpy2.robjects as ro
import rpy2.robjects.numpy2ri
rpy2.robjects.numpy2ri.activate()

nr,nc = B.shape
Br = ro.r.matrix(B, nrow=nr, ncol=nc)

ro.r.assign("B", Br)

edited May 23 '17 at 12:16

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answered Dec 04 '14 at 20:58

fileunderwater

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How to convert numpy array to R matrix?

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