Fix No Module Named Bokeh Error in Python

When working with data visualization in Python, you might encounter the "No module named Bokeh" error. This error typically occurs when trying to import the Bokeh library without proper installation or configuration.

Understanding the Error

The error appears when you try to import Bokeh in your Python script but the module isn't installed in your Python environment. Here's an example of the error:

from bokeh.plotting import figure, show

ImportError: No module named bokeh

Common Causes

Several factors can trigger this error:

1. Bokeh package not installed in your Python environment

2. Using the wrong Python environment or virtual environment

3. Incorrect installation method or package name spelling

How to Fix the Error

Method 1: Installing Bokeh Using pip

The most straightforward solution is installing Bokeh using pip. Open your terminal or command prompt and run:

pip install bokeh

For a specific version, use:

pip install bokeh==2.4.3  # Replace with desired version

Method 2: Using Conda

If you're using Anaconda, install Bokeh using conda:

conda install bokeh

Verifying Installation

After installation, verify Bokeh is properly installed by checking its version:

import bokeh
print(bokeh.__version__)

Basic Usage Example

Here's a simple example to confirm Bokeh is working correctly. This code creates a basic line plot:

from bokeh.plotting import figure, show
import numpy as np

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

# Create the plot
p = figure(title="Simple Bokeh Example", x_axis_label='x', y_axis_label='y')
p.line(x, y, line_width=2)

# Show the plot
show(p)

Troubleshooting Tips

If you're still experiencing issues, try these troubleshooting steps:

1. Check Python Environment: Ensure you're using the correct Python environment where Bokeh is installed.

2. Verify Dependencies: Bokeh requires other packages like numpy and pillow. Install them if needed.

3. Clear pip Cache: Sometimes, clearing the pip cache can resolve installation issues:

pip cache purge
pip install bokeh --no-cache-dir

Virtual Environment Considerations

It's recommended to use virtual environments for Python projects. Here's how to set up Bokeh in a virtual environment:

# Create and activate virtual environment
python -m venv bokeh_env
source bokeh_env/bin/activate  # On Windows: bokeh_env\Scripts\activate

# Install Bokeh
pip install bokeh

Additional Resources

For more detailed information about installing and using Bokeh, check out our comprehensive guide on How to Install and Get Started with Python Bokeh.

Conclusion

The "No module named Bokeh" error is usually easily resolved by properly installing the package. Remember to use the correct installation method for your setup and verify the installation.

Key takeaways: Always check your Python environment, use virtual environments when possible, and ensure all dependencies are properly installed.