5. Understanding the Figure Object

How to do it

Creating and Inspecting Figures with Plotly Express

1. Import Plotly Express. Typically, this module is importe as px

import plotly.express as px

2. Create a Figure using the Plotly Express function line, and check its type

fig = px.line(x=[0, 1, 2, 3, 4], y=[0, 1, 4, 9, 16],  markers=True,
              title="Hello Plotly Express!")

type(fig)

plotly.graph_objs._figure.Figure

3. Use the method show to render the Figure

fig.show()

4. Inspect the two main attributes of a Figure object, namely data and layout

fig.data

(Scatter({
     'hovertemplate': 'x=%{x}<br>y=%{y}<extra></extra>',
     'legendgroup': '',
     'line': {'color': '#636efa', 'dash': 'solid'},
     'marker': {'symbol': 'circle'},
     'mode': 'lines+markers',
     'name': '',
     'orientation': 'v',
     'showlegend': False,
     'x': array([0, 1, 2, 3, 4]),
     'xaxis': 'x',
     'y': array([ 0,  1,  4,  9, 16]),
     'yaxis': 'y'
 }),)

fig.layout

Layout({
    'legend': {'tracegroupgap': 0},
    'template': '...',
    'title': {'text': 'Hello Plotly Express!'},
    'xaxis': {'anchor': 'y', 'domain': [0.0, 1.0], 'title': {'text': 'x'}},
    'yaxis': {'anchor': 'x', 'domain': [0.0, 1.0], 'title': {'text': 'y'}}
})

Creating the same Figure with Plotly Graph Objects

1. Import the Plotly Graph Objects module. Typically this is importe as go

import plotly.graph_objects as go

2. Create an empty Figure object with go and check its type

fig = go.Figure()
type(fig)

plotly.graph_objs._figure.Figure

3. Render your object using the method show. Notice that this figure is completely empty.

fig.show()

4. Inspect the two main attributes of a Figure object, namely data and layout

fig.data

()

fig.layout

Layout({
    'template': '...'
})

5. Here we are going to reproduce the scatter plot that we made with Plotly Express. To do this, start by creating a new empty Figure object. Then use the methods

• add_trace

• update_layout

to add the scatter, and customise the title and the axis labels, respectively. Finally, use the method show to render your figure.

fig = go.Figure()
fig.add_trace(go.Scatter(x=[0, 1, 2, 3, 4], y=[0, 1, 4, 9, 16]))
fig.update_layout(title="Hello Plotly Go!", xaxis_title="x", yaxis_title="y")
fig.show()

6. Inspect the data and layout attributes for this new figure.

fig.data

(Scatter({
     'x': [0, 1, 2, 3, 4], 'y': [0, 1, 4, 9, 16]
 }),)

fig.layout

Layout({
    'template': '...',
    'title': {'text': 'Hello Plotly Go!'},
    'xaxis': {'title': {'text': 'x'}},
    'yaxis': {'title': {'text': 'y'}}
})