The fig.write_html() method in Plotly is a powerful tool for saving your interactive visualizations as standalone HTML files. Let's explore how to use this functionality effectively.

Basic Usage of fig.write_html()

Let's start with a simple example of creating and saving a Plotly figure as an HTML file:

import plotly.graph_objects as go
import numpy as np

# Create sample data
x = np.linspace(0, 10, 100)
y = np.sin(x)

# Create figure
fig = go.Figure()
fig.add_trace(go.Scatter(x=x, y=y, name='Sine Wave'))

# Save as HTML file
fig.write_html('sine_wave.html')

When you open 'sine_wave.html' in a web browser, you'll see a fully interactive Plotly figure that can be zoomed, panned, and explored just like in Jupyter notebooks.

Customizing HTML Output

The write_html() method offers several customization options. Here's how to use some of the most important parameters:

fig.write_html(
    'custom_figure.html',
    full_html=True,           # Generate complete HTML file
    include_plotlyjs=True,    # Include Plotly.js library
    auto_open=True           # Automatically open in browser
)

Including Multiple Figures

You can create a single HTML file containing multiple figures. This is particularly useful for creating dashboards or reports. For more layout customization, check out Plotly Update Layout.

# Create multiple figures
fig1 = go.Figure(go.Scatter(x=[1, 2, 3], y=[4, 5, 6]))
fig2 = go.Figure(go.Bar(x=[1, 2, 3], y=[7, 8, 9]))

# Save both figures in separate div elements
with open('multiple_figures.html', 'w') as f:
    f.write('
')
    f.write(fig1.to_html(full_html=False, include_plotlyjs='cdn'))
    f.write(fig2.to_html(full_html=False, include_plotlyjs=False))
    f.write('
')

Optimizing File Size

To reduce the HTML file size, you can use CDN for Plotly.js and configure what components to include:

fig.write_html(
    'optimized_figure.html',
    include_plotlyjs='cdn',    # Use CDN
    include_mathjax=False,     # Exclude MathJax
    config={'displayModeBar': False}  # Hide mode bar
)

Advanced Configuration

For more complex visualizations, you might want to customize the interaction modes. This example shows how to combine it with Mastering Plotly Scatter Plots.

config = {
    'scrollZoom': True,
    'displaylogo': False,
    'modeBarButtonsToRemove': ['zoom2d', 'pan2d']
}

fig.write_html(
    'advanced_figure.html',
    config=config,
    auto_play=False,
    include_plotlyjs='cdn'
)

Embedding in Existing HTML

You can also generate HTML code to embed in existing web pages. This is useful when integrating with web applications:

# Generate div element only
html_string = fig.to_html(
    full_html=False,
    include_plotlyjs='cdn',
    div_id='my_plot'
)

# Use in template
template = f"""



    
My Interactive Plot
    {html_string}


"""

with open('embedded_plot.html', 'w') as f:
    f.write(template)

Best Practices

File Size Management: Use CDN for Plotly.js when internet connection is available to reduce file size.

Performance: Consider using include_mathjax=False if you don't need mathematical expressions.

Compatibility: Test your HTML files across different browsers to ensure consistent behavior.

Conclusion

The fig.write_html() method is a versatile tool for saving and sharing interactive Plotly visualizations. By understanding its parameters and best practices, you can create efficient and effective HTML exports.