Unicode symbols in jupyter notebook plots (plotly3)

[Gorfar]

Hello!

I am using plotly3 for plots in Jupyter notebook. If I want to add an unicode symbol in an axis title it doesn't work, however, it worked in the plotly2.

In the following code

import plotly.graph_objs as go
layout=go.Layout()
layout.xaxis.title = u"μ"
fig = go.FigureWidget(layout=layout)
fig

I get the error " 'ascii' codec can't encode character u'\u03bc' in position 0: ordinal not in range(128)"

I use anaconda environment on OpenSuse Leap 42.3
conda=4.5.11
ipykernel=4.9.0
ipython=5.8.0
plotly=3.4.1
plotly-orca=1.1.1
python=2.7.15

[jonmmease]

Thanks for taking the time to report this @Gorfar, this looks like a problem on Python 2.

On Python 3.6:

import plotly.graph_objs as go
layout=go.Layout()
layout.xaxis.title = u"μ"
fig = go.FigureWidget(layout=layout)
fig

On Python 2.7:

---------------------------------------------------------------------------
UnicodeEncodeError                        Traceback (most recent call last)
<ipython-input-1-e0358ce99901> in <module>()
      1 import plotly.graph_objs as go
      2 layout=go.Layout()
----> 3 layout.xaxis.title = u"μ"
      4 fig = go.FigureWidget(layout=layout)
      5 fig

/Users/jmmease/Plotly/repos/plotly.py/plotly/basedatatypes.py in __setattr__(self, prop, value)
   2836                 prop in self._validators):
   2837             # Let known properties and private properties through
-> 2838             super(BasePlotlyType, self).__setattr__(prop, value)
   2839         else:
   2840             # Raise error on unknown public properties

/Users/jmmease/Plotly/repos/plotly.py/plotly/graph_objs/layout/_xaxis.py in title(self, val)
   1798     @title.setter
   1799     def title(self, val):
-> 1800         self['title'] = val
   1801 
   1802     # titlefont

/Users/jmmease/Plotly/repos/plotly.py/plotly/basedatatypes.py in __setitem__(self, prop, value)
   2808             # ### Handle simple property ###
   2809             else:
-> 2810                 self._set_prop(prop, value)
   2811 
   2812         # Handle non-scalar case

/Users/jmmease/Plotly/repos/plotly.py/plotly/basedatatypes.py in _set_prop(self, prop, val)
   3044                 return
   3045             else:
-> 3046                 raise err
   3047 
   3048         # val is None

UnicodeEncodeError: 'ascii' codec can't encode character u'\u03bc' in position 0: ordinal not in range(128)

There is some exception handling obscuring the strack trace, but I think the issue is with the use of str in the StringValidator class.

plotly.py/_plotly_utils/basevalidators.py

Lines 968 to 969 in 618ee2d

	# Convert value to a string
	v = str(v)

plotly.py/_plotly_utils/basevalidators.py

Lines 941 to 944 in 618ee2d

	# Convert all elements other than None to strings
	# Leave None as is, Plotly.js will decide how to handle
	# these null values.
	v = [str(e) if e is not None else None for e in v]

We should only really do these str conversions if the input value isn't alreadyof type str or unicode.