René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Transforms Cannot be Added to Subplots in Python3","articleBody":"### Bug report\r\n\r\n**Bug summary**\r\n\r\nAxes with transforms (PolarTransform or CompositeGenericTransform) cannot be added to a subplot in python3. This appears to be due to the fact that matplotlib fails to create a hashable version of these objects for the purpose of making a dictionary key in https://github.com/matplotlib/matplotlib/blob/1bfc7551f32f7b42ba50620a837f03e51d5b7c77/lib/matplotlib/figure.py#L823-L851. There is no bug in the python2 version.\r\n\r\n**Code for reproduction**\r\n\r\n- Minimum working code:\r\n\r\n```python\r\n%pylab inline\r\nimport matplotlib as mpl\r\nfrom matplotlib import pyplot as plt\r\n\r\nimport mpl_toolkits.axisartist.floating_axes as floating_axes\r\n\r\ntr_rotate   = mpl.transforms.Affine2D().rotate(3.1459)\r\ntr          = mpl.projections.polar.PolarTransform() +tr_rotate\r\ngrid_helper = floating_axes.GridHelperCurveLinear(tr, extremes=(0, 6.28318, 10., 20.))\r\n\r\nfig         = plt.figure()\r\nax1         = floating_axes.FloatingSubplot(fig, 111, grid_helper=grid_helper)\r\n\r\nfig.add_subplot(ax1, transform=tr)\r\n```\r\n\r\n**Actual outcome**\r\n- Traceback from using python3 running in a Jupyter notebook:\r\n```\r\n---------------------------------------------------------------------------\r\nTypeError                                 Traceback (most recent call last)\r\n/usr/local/lib/python3.5/dist-packages/matplotlib/figure.py in add(self, key, a)\r\n    122         try:\r\n--\u003e 123             hash(key)\r\n    124         except TypeError:\r\n\r\nTypeError: unhashable type: 'CompositeGenericTransform'\r\n\r\nDuring handling of the above exception, another exception occurred:\r\n\r\nTypeError                                 Traceback (most recent call last)\r\n\u003cipython-input-2-d333d90be1c9\u003e in \u003cmodule\u003e()\r\n     11 ax1         = floating_axes.FloatingSubplot(fig, 111, grid_helper=grid_helper)\r\n     12 \r\n---\u003e 13 fig.add_subplot(ax1, transform=tr)\r\n\r\n/usr/local/lib/python3.5/dist-packages/matplotlib/figure.py in add_subplot(self, *args, **kwargs)\r\n   1021             a = subplot_class_factory(projection_class)(self, *args, **kwargs)\r\n   1022 \r\n-\u003e 1023         self._axstack.add(key, a)\r\n   1024         self.sca(a)\r\n   1025         a._remove_method = self.__remove_ax\r\n\r\n/usr/local/lib/python3.5/dist-packages/matplotlib/figure.py in add(self, key, a)\r\n    123             hash(key)\r\n    124         except TypeError:\r\n--\u003e 125             raise ValueError(\"first argument, %s, is not a valid key\" % key)\r\n    126 \r\n    127         a_existing = self.get(key)\r\n\r\nTypeError: not all arguments converted during string formatting\r\n```\r\n\r\n**Expected outcome**\r\n\r\n- Figure generated by python2 in a Jupyter notebook:\r\n\r\n![download](https://cloud.githubusercontent.com/assets/1831182/24422910/2f878dd2-13c9-11e7-85f3-2f7479b244a8.png)\r\n\r\n**Matplotlib version**\r\n\r\n- Matplotlib version: 2.0.0\r\n- Python version: 3.5.2 (bug) / 2.7.12 (working)\r\n- Platform: Ubuntu 16.04\r\n\r\n- Python was installed using apt.\r\n- Matplotlib was installed using pip.","author":{"url":"https://github.com/w2naf","@type":"Person","name":"w2naf"},"datePublished":"2017-03-28T19:18:02.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/8395/matplotlib/issues/8395"}