使用rpy2和ggplot在jupyter中显示图

Question

我正在尝试在Jupyter笔记本中遵循here中的教程。为此，我正在运行提供的所有代码，不同之处在于，我尝试按照rpy2教程中的指示运行robjects。但是，如何使图块起作用呢？：

ro.r('''
    [remaining code]
    gp = ggplot2.ggplot(mtcars)
    pp = gp + ggplot2.aes_string(x='wt', y='mpg') + ggplot2.geom_point()
    pp.plot()
    ''')

这不返回任何内容。如果我这样做：

p=ro.r('''
      ggplot(mtcars)
      ''')
p

它返回以下错误：

TypeError: 'NULLType' object is not iterable

R object with classes: ('gg', 'ggplot') mapped to:
[ListSexpV..., ListSexpV..., SexpEnvir..., ListSexpV..., ..., SexpEnvir..., SexpEnvir..., SexpEnvir..., ListSexpV...]
  data: <class 'rpy2.rinterface.ListSexpVector'>
  <rpy2.rinterface.ListSexpVector object at 0x2b6e6f8e7ec8> [RTYPES.VECSXP]
  layers: <class 'rpy2.rinterface.ListSexpVector'>
  <rpy2.rinterface.ListSexpVector object at 0x2b6e6f8e7a48> [RTYPES.VECSXP]
  scales: <class 'rpy2.rinterface.SexpEnvironment'>
  <rpy2.rinterface.SexpEnvironment object at 0x2b6e6f8e7e08> [RTYPES.ENVSXP]
  mapping: <class 'rpy2.rinterface.ListSexpVector'>
  <rpy2.rinterface.ListSexpVector object at 0x2b6e6f8e7f48> [RTYPES.VECSXP]
  theme: <class 'rpy2.rinterface.ListSexpVector'>
  <rpy2.rinterface.ListSexpVector object at 0x2b6e6f8e7ec8> [RTYPES.VECSXP]
  coordinates: <class 'rpy2.rinterface.SexpEnvironment'>
  <rpy2.rinterface.SexpEnvironment object at 0x2b6e6f8e7e88> [RTYPES.ENVSXP]
  facet: <class 'rpy2.rinterface.SexpEnvironment'>
  <rpy2.rinterface.SexpEnvironment object at 0x2b6e6f8e7f48> [RTYPES.ENVSXP]
  plot_env: <class 'rpy2.rinterface.SexpEnvironment'>
  <rpy2.rinterface.SexpEnvironment object at 0x2b6e6f8e7e08> [RTYPES.ENVSXP]
  labels: <class 'rpy2.rinterface.ListSexpVector'>
  <rpy2.rinterface.ListSexpVector object at 0x2b6e6f8e7ec8> [RTYPES.VECSXP]