Hover text with Plotly Express¶

Many Plotly Express functions support configurable hover text. The hover_data argument accepts a list of column names to be added to the hover tooltip. The hover_name property controls which column is displayed in bold as the tooltip title.

Here is an example that creates a scatter plot using Plotly Express with custom hover data and a custom hover name.

In [1]:

import plotly.express as px

gapminder_2007 = px.data.gapminder().query("year==2007")

fig = px.scatter(gapminder_2007, x="gdpPercap", y="lifeExp", log_x=True,
                 hover_name="country", hover_data=["continent"])

fig.show()

Add Hover Text¶

In [2]:

import plotly.graph_objects as go

fig = go.Figure()

fig.add_trace(go.Scatter(
    x=[1, 2, 3, 4, 5],
    y=[2, 1, 6, 4, 4],
    hovertext=["Text A", "Text B", "Text C", "Text D", "Text E"],
    hoverinfo="text",
    marker=dict(
        color="green"
    ),
    showlegend=False
))

fig.show()

Format Hover Text¶

In [3]:

import plotly.graph_objects as go


fig = go.Figure(go.Scatter(
    x=[1, 2, 3, 4, 5],
    y=[2.02825, 1.63728, 6.83839, 4.8485, 4.73463],
    hoverinfo="y",
    marker=dict(
        color="green"
    ),
    showlegend=False
))

fig.update_layout(
    title_text=("Set hover text formatting<br>" +
                "<a href= https://github.com/d3/d3-time-format/blob/master/README.md#locale_format>" +
                "https://github.com/d3/d3-time-format/blob/master/README.md#locale_format</a>"),
    title_font=dict(
        size=10
    ),
)

fig.update_xaxes(zeroline=False)
fig.update_yaxes(hoverformat=".2f")

fig.show()

To customize the tooltip on your graph you can use hovertemplate, which is a template string used for rendering the information that appear on hoverbox. This template string can include variables in %{variable} format, numbers in d3-format's syntax, and date in d3-time-format's syntax. Hovertemplate customize the tooltip text vs. texttemplate which customizes the text that appears on your chart.
Set the horizontal alignment of the text within tooltip with hoverlabel.align.

In [4]:

import plotly.graph_objects as go

fig = go.Figure(go.Scatter(
    x = [1,2,3,4,5],
    y = [2.02825,1.63728,6.83839,4.8485,4.73463],
    hovertemplate =
    '<i>Price</i>: $%{y:.2f}'+
    '<br><b>X</b>: %{x}<br>'+
    '<b>%{text}</b>',
    text = ['Custom text {}'.format(i + 1) for i in range(5)],
    showlegend = False))

fig.add_trace(go.Scatter(
    x = [1,2,3,4,5],
    y = [3.02825,2.63728,4.83839,3.8485,1.73463],
    hovertemplate = 'Price: %{y:$.2f}<extra></extra>',
    showlegend = False))

fig.update_layout(
    hoverlabel_align = 'right', 
    title = "Set hover text with hovertemplate")

fig.show()

In [5]:

import plotly.graph_objects as go

fig = go.Figure(go.Pie(
    name = "",
    values = [2, 5, 3, 2.5],
    labels = ["R", "Python", "Java Script", "Matlab"],
    text = ["textA", "TextB", "TextC", "TextD"],
    hovertemplate = "%{label}: <br>Popularity: %{percent} </br> %{text}"
))

fig.show()

Advanced Hover Template¶

The following example shows how to format hover template. Here is an example to see how to format hovertemplate in Dash.

In [6]:

import plotly.graph_objects as go
import plotly.express as px
import pandas as pd
import math

data = px.data.gapminder()
df_2007 = data[data['year']==2007]
df_2007 = df_2007.sort_values(['continent', 'country'])

bubble_size = []

for index, row in df_2007.iterrows():
    bubble_size.append(math.sqrt(row['pop']))

df_2007['size'] = bubble_size
continent_names = ['Africa', 'Americas', 'Asia', 'Europe', 'Oceania']
continent_data = {continent:df_2007.query("continent == '%s'" %continent)
                              for continent in continent_names}

fig = go.Figure()

for continent_name, continent in continent_data.items():
    fig.add_trace(go.Scatter(
        x=continent['gdpPercap'],
        y=continent['lifeExp'],
        name=continent_name,
        text=df_2007['continent'],
        hovertemplate=
        "<b>%{text}</b><br><br>" +
        "GDP per Capita: %{y:$,.0f}<br>" +
        "Life Expectation: %{x:.0%}<br>" +
        "Population: %{marker.size:,}" +
        "<extra></extra>",
        marker_size=continent['size'],
        ))

fig.update_traces(
    mode='markers',
    marker={'sizemode':'area',
            'sizeref':10})

fig.update_layout(
    xaxis={
        'title':'GDP per capita',
        'type':'log'},
    yaxis={'title':'Life Expectancy (years)'})

fig.show()

Adding other data to the hover with customdata and a hovertemplate¶

go traces have a customdata argument in which you can add an array, which outer dimensions should have the same dimensions as the plotted data. You can then use customdata inside a hovertemplate to display the value of customdata.

In [7]:

import plotly.graph_objects as go
from plotly.subplots import make_subplots
import numpy as np
np.random.seed(0)
z1, z2, z3 = np.random.random((3, 7, 7))
customdata = np.dstack((z2, z3))
fig = make_subplots(1, 2, subplot_titles=['z1', 'z2'])
fig.add_trace(go.Heatmap(
    z=z1, 
    customdata=np.dstack((z2, z3)),
    hovertemplate='<b>z1:%{z:.3f}</b><br>z2:%{customdata[0]:.3f} <br>z3: %{customdata[1]:.3f} ',
    coloraxis="coloraxis1", name=''),
    1, 1)
fig.add_trace(go.Heatmap(
    z=z2, 
    customdata=np.dstack((z1, z3)),
    hovertemplate='z1:%{customdata[0]:.3f} <br><b>z2:%{z:.3f}</b><br>z3: %{customdata[1]:.3f} ',
    coloraxis="coloraxis1", name=''),
    1, 2)
fig.update_layout(title_text='Hover to see the value of z1, z2 and z3 together')
fig.show()

Set Hover Template in Mapbox¶

In [8]:

import plotly.graph_objects as go

token = open(".mapbox_token").read() # you need your own token

fig = go.Figure(go.Scattermapbox(
    name = "",
    mode = "markers+text+lines",
    lon = [-75, -80, -50],
    lat = [45, 20, -20],
    marker = {'size': 20, 'symbol': ["bus", "harbor", "airport"]},
    hovertemplate =
    "<b>%{marker.symbol} </b><br><br>" +
    "longitude: %{lon}<br>" +
    "latitude: %{lat}<br>" ))

fig.update_layout(
    mapbox = {
        'accesstoken': token,
        'style': "outdoors", 'zoom': 1},
    showlegend = False)

fig.show()

Reference¶

See https://plot.ly/python/reference/ for more information and chart attribute options!

Hover Text and Formatting in Python