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Gantt

Gantt Charts in Python

How to make Gantt Charts in Python with Plotly. Gantt Charts use horizontal bars to represent the start and end times of tasks.


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A Gantt chart is a type of bar chart that illustrates a project schedule. The chart lists the tasks to be performed on the vertical axis, and time intervals on the horizontal axis. The width of the horizontal bars in the graph shows the duration of each activity.

In [1]:

import plotly.express as px
import pandas as pd

df = pd.DataFrame([
    dict(Task="Job A", Start='2009-01-01', Finish='2009-02-28'),
    dict(Task="Job B", Start='2009-03-05', Finish='2009-04-15'),
    dict(Task="Job C", Start='2009-02-20', Finish='2009-05-30')
])

fig = px.timeline(df, x_start="Start", x_end="Finish", y="Task")
fig.update_yaxes(autorange="reversed") # otherwise tasks are listed from the bottom up
fig.show()

In [2]:

import plotly.express as px
import pandas as pd

df = pd.DataFrame([
    dict(Task="Job A", Start='2009-01-01', Finish='2009-02-28', Resource="Alex"),
    dict(Task="Job B", Start='2009-03-05', Finish='2009-04-15', Resource="Alex"),
    dict(Task="Job C", Start='2009-02-20', Finish='2009-05-30', Resource="Max")
])

fig = px.timeline(df, x_start="Start", x_end="Finish", y="Task", color="Resource")
fig.update_yaxes(autorange="reversed")
fig.show()

In [3]:

import plotly.express as px
import pandas as pd

df = pd.DataFrame([
    dict(Task="Job A", Start='2009-01-01', Finish='2009-02-28', Completion_pct=50),
    dict(Task="Job B", Start='2009-03-05', Finish='2009-04-15', Completion_pct=25),
    dict(Task="Job C", Start='2009-02-20', Finish='2009-05-30', Completion_pct=75)
])

fig = px.timeline(df, x_start="Start", x_end="Finish", y="Task", color="Completion_pct")
fig.update_yaxes(autorange="reversed")
fig.show()

It is also possible to have multiple bars on the same horizontal line, say by resource:

Note: When setting color to the same value as y, autorange should not be set to reverse, so as to list the value of the Y axis in the same order as the legend entries.

In [4]:

import plotly.express as px
import pandas as pd

df = pd.DataFrame([
    dict(Task="Job A", Start='2009-01-01', Finish='2009-02-28', Resource="Alex"),
    dict(Task="Job B", Start='2009-03-05', Finish='2009-04-15', Resource="Alex"),
    dict(Task="Job C", Start='2009-02-20', Finish='2009-05-30', Resource="Max")
])

fig = px.timeline(df, x_start="Start", x_end="Finish", y="Resource", color="Resource")
fig.show()

Deprecated Figure Factory

Prior to the introduction of plotly.express.timeline() in version 4.9, the recommended way to make Gantt charts was to use the now-deprecated create_gantt() figure factory, as follows:

In [5]:

import plotly.figure_factory as ff

df = [dict(Task="Job A", Start='2009-01-01', Finish='2009-02-28'),
      dict(Task="Job B", Start='2009-03-05', Finish='2009-04-15'),
      dict(Task="Job C", Start='2009-02-20', Finish='2009-05-30')]

fig = ff.create_gantt(df)
fig.show()

Group Tasks Together

The following example shows how to use the now-deprecated create_gantt() figure factory to color tasks by a numeric variable.

In [6]:

import plotly.figure_factory as ff

df = [dict(Task="Job-1", Start='2017-01-01', Finish='2017-02-02', Resource='Complete'),
      dict(Task="Job-1", Start='2017-02-15', Finish='2017-03-15', Resource='Incomplete'),
      dict(Task="Job-2", Start='2017-01-17', Finish='2017-02-17', Resource='Not Started'),
      dict(Task="Job-2", Start='2017-01-17', Finish='2017-02-17', Resource='Complete'),
      dict(Task="Job-3", Start='2017-03-10', Finish='2017-03-20', Resource='Not Started'),
      dict(Task="Job-3", Start='2017-04-01', Finish='2017-04-20', Resource='Not Started'),
      dict(Task="Job-3", Start='2017-05-18', Finish='2017-06-18', Resource='Not Started'),
      dict(Task="Job-4", Start='2017-01-14', Finish='2017-03-14', Resource='Complete')]

colors = {'Not Started': 'rgb(220, 0, 0)',
          'Incomplete': (1, 0.9, 0.16),
          'Complete': 'rgb(0, 255, 100)'}

fig = ff.create_gantt(df, colors=colors, index_col='Resource', show_colorbar=True,
                      group_tasks=True)
fig.show()

Color by Numeric Variable

The following example shows how to use the now-deprecated create_gantt() figure factory to color tasks by a numeric variable.

In [7]:

import plotly.figure_factory as ff

df = [dict(Task="Job A", Start='2009-01-01', Finish='2009-02-28', Complete=10),
      dict(Task="Job B", Start='2008-12-05', Finish='2009-04-15', Complete=60),
      dict(Task="Job C", Start='2009-02-20', Finish='2009-05-30', Complete=95)]

fig = ff.create_gantt(df, colors='Viridis', index_col='Complete', show_colorbar=True)
fig.show()

Reference

What About Dash?

Dash is an open-source framework for building analytical applications, with no Javascript required, and it is tightly integrated with the Plotly graphing library.

Learn about how to install Dash at https://dash.plot.ly/installation.

Everywhere in this page that you see fig.show(), you can display the same figure in a Dash application by passing it to the figure argument of the Graph component from the built-in dash_core_components package like this:

import plotly.graph_objects as go # or plotly.express as px
fig = go.Figure() # or any Plotly Express function e.g. px.bar(...)
# fig.add_trace( ... )
# fig.update_layout( ... )

from dash import Dash, dcc, html

app = Dash()
app.layout = html.Div([
    dcc.Graph(figure=fig)
])

app.run(debug=True, use_reloader=False)  # Turn off reloader if inside Jupyter