Working with Python Packages

Python Online allows you to enhance your programs by installing and using Python packages directly within the platform. This section will guide you through the process of installing packages, managing dependencies, and understanding compatibility.

Installing Python Packages

Using the Package Input Field:
Locate the pip install section in the editor panel.

Enter the package name in the input field (e.g., numpy).

Click the Install Button ().
Package Installation Process:
The platform checks if the package is available and compatible with Pyodide.

If compatible, the package is downloaded and installed.

You’ll see a confirmation message in the output panel once the installation is complete.
Example:
Install the numpy package, then run the following code:
```
import numpy as np
array = np.array([1, 2, 3])
print(array)
```

List Preloaded and Installed Packages

You can list all the installed packages and their versions by using the importlib.metadata module. This method is the most up-to-date and avoids deprecated warnings.

Here's how you can do it:

from importlib.metadata import distributions

# List all installed packages and their versions
for dist in distributions():
    print(f"{dist.metadata['Name']}: {dist.version}")

Managing Dependencies

Python Online supports a wide range of Python packages, but there are some limitations due to the browser-based environment:

Only pure Python packages or those compatible with WebAssembly (WASM) can be installed.
Packages requiring compiled C extensions might not be supported.

To check if a package is compatible:

Enter the package name in the pip install field and attempt installation.
If incompatible, an error message will indicate the issue.

Built-In Modules

Some commonly used Python modules are pre-installed. You can see the complete list of built-in modules here.

To use these packages, use the packages input field at the bottom of the editor to load them.

Installing from PyPI

Packages hosted on the Python Package Index (PyPI) can be installed directly if they meet compatibility requirements:

Example: Install requests:

pip install requests

Common Errors During Installation

Package Not Found:

Ensure the package name is spelled correctly.

Example error:

The package 'xyz' does not exist on PyPI. Please check the spelling or availability.

Incompatible Package:
Some packages may not be compatible with the Pyodide environment.

Example error:
```
⛔ Sorry! but the package 'xyz' is not compatible and cannot be installed.
```
Dependencies Missing:
Certain packages may rely on dependencies that are unavailable or incompatible.
```
⛔ Failed to install 'xyz' because a required dependency is not compatible.
```

Troubleshooting

Error: "Module Not Found":
- Ensure the package is installed using the pip interface.
- Re-check spelling and compatibility.
Long Installation Times:
Package installation might take longer depending on the size of the package and network conditions.

Best Practices

Install Only Necessary Packages:
Keep your workspace lightweight by installing only what you need.
Test Installations:
After installing a package, run a simple script to ensure it’s functioning as expected.

Example:
```
import pandas as pd
print(pd.__version__)
```
Explore Built-In Modules First:
Before installing external packages, check if the required functionality is available in Python’s built-in modules.

With Python Online’s package management capabilities, you can leverage the power of Python’s extensive library ecosystem directly from your browser. Whether you need data analysis tools, web frameworks, or scientific libraries, the platform has you covered! 📦