> library(rPython)
Loading required package: RJSONIO
> ### load r data.frame ###
> data(iris)
> r_df1 <- iris
> class(r_df1)
[1] "data.frame"
> head(r_df1, n = 3)
  Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa
3          4.7         3.2          1.3         0.2  setosa
> ### pass r data.frame to python dict ###
> python.assign('py_dict1', r_df1)
> python.exec('print type(py_dict1)')
<type 'dict'>
> ### convert python dict to pandas DataFrame ###
> python.exec('import pandas as pd')
> python.exec('py_df = pd.DataFrame(py_dict1)')
> python.method.call('py_df', 'info')
<class 'pandas.core.frame.DataFrame'>
Int64Index: 150 entries, 0 to 149
Data columns (total 5 columns):
Petal.Length    150  non-null values
Petal.Width     150  non-null values
Sepal.Length    150  non-null values
Sepal.Width     150  non-null values
Species         150  non-null values
dtypes: float64(4), object(1)NULL
> python.exec('print py_df.head(3)')
   Petal.Length  Petal.Width  Sepal.Length  Sepal.Width Species
0           1.4          0.2           5.1          3.5  setosa
1           1.4          0.2           4.9          3.0  setosa
2           1.3          0.2           4.7          3.2  setosa
> ### convert pandas DataFrame back to dict ###
> python.exec('py_dict2 = py_df.to_dict(outtype = "list")') 
> ### pass python dict back to r list ###
> r_list <- python.get('py_dict2')
> class(r_list)
[1] "list"
> ### convert r list to r data.frame ###
> r_df2 <- data.frame(r_list)
> class(r_df2)
[1] "data.frame"
> head(r_df2, n = 3)
  Petal.Length Sepal.Length Petal.Width Sepal.Width Species
1          1.4          5.1         0.2         3.5  setosa
2          1.4          4.9         0.2         3.0  setosa
3          1.3          4.7         0.2         3.2  setosa