Once again, I am having a great time with Notebook and the emerging rmagic infrastructure, but I have another question about the bridge between the two. Currently I am attempting to pass several subsets of a pandas DataFrame to R for visualization with ggplot2. Just to be clear upfront, I know that I could pass the entire DataFrame and perform additional subsetting in R. My preference, however, is to leverage the data management capability of Python and the subset-wise operations I am performing are just easier and faster using pandas than the equivalent operations in R. So for the sake of efficiency and morbid curiosity...
I have been trying to figure out if there is a way to push several objects at once. The wrinkle is that sometimes I don't know in advance how many items will need to be pushed. To retain flexibility, I have been populating dictionaries with DataFrames throughout the front end of the script. The following code provides a reasonable facsimile of what I am working through (I have not converted via com.convert_to_r_dataframe for simplicity, but my real code does take this step):
import pandas as pd
from pandas import DataFrame
%load_ext rmagic
d1=DataFrame(np.arange(16).reshape(4,4))
d2=DataFrame(np.arange(20).reshape(5,4))
d_list=[d1,d2]
names=['n1','n2']
d_dict=dict(zip(names,d_list))
for name in d_dict.keys():
exec '%s=d_dict[name]' % name
%Rpush n1
As can be seen, I can assign a static name and push the DataFrame into the R namespace individually (as well as in a 'list' >> %Rpush n1 n2). What I cannot do is something like the following:
for name in d_dict.keys():
%Rpush d_dict[name]
That snippet raises an exception >> KeyError: u'd_dict[name]'. I also tried to deposit the dynamically named DataFrames in a list, the list references end up pointing to the data rather than the object reference:
df_list=[]
for name in d_dict.keys():
exec '%s=d_dict[name]' % name
exec 'df_list.append(%s)' % name
print df_list
for df in df_list:
%Rpush df
[ 0 1 2 3
0 0 1 2 3
1 4 5 6 7
2 8 9 10 11
3 12 13 14 15,
0 1 2 3
0 0 1 2 3
1 4 5 6 7
2 8 9 10 11
3 12 13 14 15
4 16 17 18 19]
%Rpush did not throw an exception when I looped through the lists contents, but the DataFrames could not be found in the R namespace. I have not been able to find much discussion of this topic beyond talk about the conversion of lists to R vectors. Any help would be greatly appreciated!
