Pandas Categorical Index with Bokeh high-level charting API

siddhartha.a.gandhiAug 27, 2016 #1

It seems as though Bokeh’s high-level charting API, for instance bokeh.charts.Bar, does not respect the order inherent in a Pandas Categorical Index. One data series I was looking at contained Moody’s ratings (see Bond credit rating - Wikipedia for the scale). Alphabetical order would place the “A1” value first. When I use bokeh.charts.Bar, in fact, A1 is the first value on the left of the chart.

To solve this, I attempted to use an ordered Pandas categorical index for the series I pass in, which explicitly places “Aaa” first, and “Aa1” second, etc., but this does not seem to change anything in the resulting bar plot.

I will post example code and plots shortly, just wanted to start this discussion, to see what others’ experience has been.

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birdsarah_continuumAug 27, 2016 #2

There’s an option to
not sort. I’ve forgotten how to use it - I’m pretty sure it’s in an example somewhere.

···

On 8/27/16 11:26 AM,
wrote:

siddhartha.a.gandhi@gmail.com

    It seems as though Bokeh's high-level charting API,
for instance bokeh.charts.Bar, does not respect the order
inherent in a Pandas Categorical Index. One data series I was
looking at contained Moody’s ratings
(see
for the scale). Alphabetical order would place the “A1” value
first. When I use bokeh.charts.Bar, in fact, A1 is the first
value on the left of the chart.

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https://en.wikipedia.org/wiki/Bond_credit_rating#Credit_rating_tiers

      To solve this, I attempted to use an ordered Pandas

categorical index for the series I pass in, which explicitly
places “Aaa” first, and “Aa1” second, etc., but this does not
seem to change anything in the resulting bar plot.

        I will post example code and plots shortly, just wanted

to start this discussion, to see what others’ experience has
been.

⌁ Link to post