Plotly: How to add elements to hover_data using plotly.express piechart?
I am playing with examples from plotly.express piechart help page and trying to add an extra element iso_num
to the hover_data property (iso_num
is an int64 column in the gapminder dataframe)
import plotly.express as px
df = px.data.gapminder().query("year == 2007").query("continent == 'Americas'")
fig = px.pie(df, values='pop', names='country',
title='Population of American continent',
hover_data=['lifeExp','iso_num'], labels={'lifeExp':'life expectancy','iso_num':'iso num'
})
fig.update_traces(textposition='inside', textinfo='percent+label')
fig.show()
Hovering over the slice of the pie chart then gives this:
where iso num
value is %{customdata[1]}
instead of the numeric value from the column.
What am I missing?
Thanks!
This seems to be a relic from back when it was stated that
Oh pie hover is a big mess
Which since seems to be have been resolved. But perhaps not for px.pie()
?
I've tried numerous approaches, but I'm only able to get the customdata + hovertemplate approach to work for go.Pie
and not for px.Pie
. Here's a demonstration on how assigning values to customdata
will make any variable otherwise not assigned to go.Pie()
available for a custom hovertamplate:
Plot:
Code:
import plotly.graph_objects as go
import plotly.express as px
df = px.data.gapminder().query("year == 2007").query("continent == 'Americas'")
fig = go.Figure(go.Pie(
name = "",
values = df['pop'],
labels = df['country'],
customdata=df['iso_num'],
hovertemplate = "Country:%{label}: <br>Population: %{value} </br> iso num:%{customdata}"
))
fig.show()
I found a way to do it with Plotly Express Pie chart as well. You can use update_traces
to define hover_template
. It seems there is an issue with splitting on multiple values for hover_data
/custom_data
and all values are present at 0 index only i.e. both values are at customdata[0]
.
import plotly.express as px
df = px.data.gapminder().query("year == 2007").query("continent == 'Americas'")
fig = px.pie(df, values='pop', names='country',
title='Population of American continent',
custom_data=['lifeExp','iso_num'], labels={'lifeExp':'life expectancy','iso_num':'iso num'
})
fig.update_traces(textposition='inside', textinfo='percent+label',\
hovertemplate = "Country:%{label}: <br>Population: %{value} </br>(life expentancy, iso num) : %{customdata}"
)
fig.show()
On hover: