Default conversions

This page list the default conversions between R and Python objects.

Basic types

The conversion of basic types is performed directly by the convert() and convert_python_to_r_data() functions (or the underlying Converter and ConverterFromPythonToR). Thus, changing the conversion for basic types currently requires creating a custom converter class. The default converters perform the following conversions:

R type	Python type
builtin function	rdata.conversion.RBuiltin.
bytecode	rdata.conversion.RBytecode.
char (internal)	str or bytes (depending on the encoding flags).
closure	rdata.conversion.RFunction.
complex	numpy.ndarray with 128-bits complex dtype. xarray.DataArray if it contains labeled dimensions.
environment	rdata.conversion.REnvironment. There are three special cases: the empty, base and global environments, which are all empty by default. The base and global environments may be supplied to the converter.
expression	rdata.conversion.RExpression.
external pointer	rdata.conversion.RExternalPointer.
integer	numpy.ndarray with 32-bits integer dtype. numpy.ma.MaskedArray with 32-bits integer dtype if it contains NA values. xarray.DataArray if it contains labeled dimensions.
language	rdata.conversion.RLanguage.
list / vector	list (if untagged). dict (if tagged). Empty lists are considered tagged.
logical (boolean)	numpy.ndarray with boolean dtype. numpy.ma.MaskedArray with boolean dtype if it contains NA values. xarray.DataArray if it contains labeled dimensions.
missing argument	NotImplemented.
NULL	None.
real	numpy.ndarray with 64-bits floating point dtype. xarray.DataArray if it contains labeled dimensions.
reference	The referenced value, that is, an object already converted.
S4 object	types.SimpleNamespace.
special function	rdata.conversion.RBuiltin.
string	numpy.ndarray with a suitable fixed-length string dtype.
symbol	str.

Custom classes

In addition, R objects containing a “class” attribute, or Python objects not listed above, are passed to an R-to-Python or Python-to-R constructor function, respectively. When the “class” attribute contains several class names, these are tried in order. A dictionary of constructor functions can be supplied to the converters as exemplified in Converting between R and Python classes. The default constructor dictionaries perform the following conversions:

R class	Python class
data.frame	pandas.DataFrame.
factor	pandas.Categorical.
ordered	pandas.Categorical (with ordered categories).
srcfile	rdata.conversion.SrcFile.
srcfilecopy	rdata.conversion.SrcFileCopy.
srcref	rdata.conversion.SrcRef.
ts	pandas.Series.