How to Debug Python in VSCode for Beginners

Debugging Python in VSCode can be a game-changer for any developer working with this versatile programming language. Visual Studio Code, with its powerful debugger and intuitive interface, provides the tools you need to catch and resolve bugs efficiently.

With extensive support for Python, including features like breakpoints, an integrated terminal, the Python extension, and launch configuration files like launch.json, VSCode stands out as an essential tool for Python developers.

By the end of this article, you’ll be equipped with the knowledge to set up the VSCode debugger, effectively use breakpoints, and navigate through your code with ease.

What you’ll learn includes:

• How to use Visual Studio Code for debugging Python scripts.
• Setting breakpoints and configuring the debugger.
• Utilizing the Python interpreter and integrated terminal.
• Managing exceptions and analyzing the call stack.

Let’s dive in to make your Python debugging process in VSCode seamless and efficient.

How to Debug Python in VSCode: Quick Workflow

Debugging Python in Visual Studio Code (VSCode) is a straightforward process that enhances your ability to identify and fix issues in your code. Here’s a step-by-step guide to help you get started.

1. Install the Python Extension

Before you can debug Python scripts, ensure that you have the Python extension installed in VSCode. You can find it in the Extensions view by searching for “Python” and installing it.

2. Open Your Python Project

Launch VSCode and open the folder containing your Python project. This allows you to access all relevant files and configurations.

3. Create a Debug Configuration

To set up debugging:

• Open the Run and Debug sidebar by clicking on the play icon or pressing Ctrl + Shift + D.
• Click on “create a launch.json file” or select “Add Configuration” if one already exists.
• Choose “Python” from the list of available configurations.

Here’s an example of a simple launch.json configuration:

4. Set Breakpoints

Breakpoints are essential for debugging as they allow you to pause execution at specific lines:

• Click in the gutter next to the line number where you want to set a breakpoint, or press F9.
• A red dot will appear, indicating an active breakpoint.

5. Start Debugging

To begin debugging your script:

• Click the green “Start Debugging” button in the Run and Debug sidebar or press F5.
• The debugger will run your code and pause at any breakpoints you’ve set.

6. Use Debugging Actions

While debugging, you can control execution with various actions:

• Continue (F5): Resume running until the next breakpoint.
• Step Over (F10): Execute the next line but skip over function calls.
• Step Into (F11): Enter into functions to see their execution.
• Step Out (Shift + F11): Exit the current function and return to its caller.

7. Inspect Variables

During a debugging session, you can inspect variable values:

• Hover over any variable in your code to see its current value.
• Use the Variables panel to view local and global variables.

8. Use the Debug Console

The Debug Console allows you to evaluate expressions and run commands while debugging, which is useful for testing fixes on-the-fly.

9. Advanced Techniques

For more advanced debugging capabilities, consider using Debugpy, which allows remote debugging and additional features:

1. Install Debugpy using pip.
2. Start your script with:
   bash

   python -m debugpy --listen 5678 myscript.py

3. Attach VSCode’s debugger to this session for enhanced control.

Conclusion

Debugging in VSCode offers powerful tools that streamline the process of identifying issues within Python scripts. By following these steps, you can effectively utilize breakpoints, inspect variables, and leverage integrated tools to enhance your coding efficiency and accuracy.

Setting Up the Debugging Environment in Visual Studio Code and Visual Studio

Installing and Configuring Essential Tools

Downloading and Setting Up VSCode or Visual Studio

First things first, head over to your web browser and download VSCode or Visual Studio from their respective official websites. For VSCode, it’s often referred to as a sleek, lightweight code editor favored by many developers. Visual Studio, on the other hand, is a more comprehensive IDE equipped with powerful features.

Download and installation are straightforward processes. Follow the prompts to complete the setup on your machine.

Installing Python and Python Extensions for VSCode

If you haven’t installed Python yet, that’s your next step. Head to the Python official site and download the latest version. Make sure to add Python to your system’s PATH.

Once done, open VSCode and navigate to the Extensions panel by clicking the square icon on the sidebar. Search for the Python extension—primarily the one provided by Microsoft. Click ‘Install’ and let VSCode handle the rest.

Setting Up the Development Environment

Creating a Virtual Environment for Python Projects

Virtual environments are crucial to keeping dependencies isolated and manageable. Open a terminal within VSCode:

python -m venv myenv

Replace “myenv” with your preferred environment name. This command creates a new virtual environment in your project directory. Activate it with:

# Windows
myenv\Scripts\activate
# macOS/Linux
source myenv/bin/activate

Now, your project’s dependencies will be isolated to this environment.

Managing Python Environments and Selecting Interpreters in Both Editors

Navigate in VSCode to the bottom left corner and click on the interpreter path. A selection panel will pop up, letting you choose the interpreter from your virtual environment.

In Visual Studio, head to the Solution Explorer. Right-click on your project and select “Python Environments.” From here, you can add or select the desired interpreter, ensuring it aligns with the environment you’ve set up in VSCode.

Managing environments in both editors ensures that the setup is consistent when switching between them, facilitating smoother debugging and reducing the risk of running into compatibility issues.

Preparing Python Projects for Debugging

Configuring a New or Existing Python Project

Steps to Open and Set Up a Python Project in VSCode

Open VSCode and hit “Open Folder” from the Welcome screen or via the File menu. Navigate to your project folder.

For a brand-new project? Create a folder manually or use mkdir in the integrated terminal. Move into that directory with cd <your-folder>. Now, initialize a Python project:

python -m venv env

Activate the virtual environment. Now install dependencies with pip install <package-names>. Don’t forget to create a main.py or equivalent starter file.

Using Project Templates and Configuring Startup Files in Visual Studio

Visual Studio offers excellent project templates. Go to File > New > Project. Choose “Python Application” if you’re starting fresh.

For existing projects, simply open the project file. Visual Studio’s Solution Explorer helps you locate and manage startup files efficiently. Rename or specify the main script to be executed. Edit configurations via the project properties.

Configuring Debug Settings

Setting Up Debug Configurations with launch.json in VSCode

Hit F5 or click the gear icon in the Debug panel. VSCode prompts you to set up a launch.json file. Select “Python File” as your default configuration. This file is a playground for setting breakpoints, variables, and more.

Edit the launch.json to fine-tune your experience. Want to use environment variables? Add them under the “env” key in your configuration:

{
    "name": "Python: Current File",
    "type": "python",
    "request": "launch",
    "program": "${file}",
    "console": "integratedTerminal",
    "env": {
        "MY_VARIABLE": "value"
    }
}

Managing Project Debugging Options and Environment Variables in Visual Studio

In Visual Studio, open the project properties and go to the Debug tab. Here, you can set command-line arguments and environment variables.

For more control, the “Environment Variables” section lets you tweak what’s passed to your Python script during execution. Always ensure correct paths, especially if using virtual environments.

Navigating Visual Studio Code and Visual Studio for Python Debugging

Understanding the Interface and Key Panels

Overview of Activity Bar, Debug Toolbar, and Code Editor in VSCode

When you fire up VSCode, the Activity Bar catches your eye on the far left. It’s where you hop between the Explorer, Search, Source Control, and Extensions.

Next up, the Debug Toolbar. Hit F5 or click the play icon to get it rolling. Here’s what you get:

• Continue: Carry on with your debugging session.
• Step Over: Jump over functions and methods.
• Step Into: Dive into the functions’ nitty-gritty.
• Step Out: Exit the current function.

Right in the middle? The Code Editor. This is your canvas, where you crank out Python code, set your breakpoints, and handle all the error messages.

Using Solution Explorer, Debug Menu, and Immediate windows in Visual Studio

Flip over to Visual Studio. The Solution Explorer is your project’s backbone, showcasing files and libraries. Want to manage your Python scripts? It’s your go-to.

Hit the Debug Menu for a toolbox of options. From starting a debug session to toggling breakpoints, it’s a comprehensive control panel. And Immediate Windows? Absolute gold.

Type in expressions, inspect variables, or even execute code snippets live. Essential for real-time debugging and code inspection.

Utilizing the Built-in Terminal and Interactive Windows

Accessing and Using the Terminal in VSCode for Debugging Commands

VSCode’s Built-in Terminal is a beast. Hit Ctrl+` (backtick) to bring it up. This terminal lets you run:

python <filename>.py
venv\Scripts\activate  # On Windows
source venv/bin/activate # On macOS/Linux

Run debugging commands, install packages, navigate directories. Integrating this with the VSCode debugger maximizes efficiency.

Leveraging Immediate and Debug Interactive Windows in Visual Studio

Visual Studio’s Immediate Window works magic. Access it under Debug > Windows > Immediate. Execute lines of code and see results in real time. Debugging a pesky error? This window gives a hands-on fix.

Debug Interactive Window offers another layer. Type, run, and execute Python snippets while you’re in a debugging session. Excellent for live troubleshooting and adjustments.

Core Debugging Techniques for Python Code

Basic Debugging Workflow

Setting and Managing Breakpoints

Breakpoints are your first line of defense against bugs. Click in the margin next to the line number, and a red dot appears. That’s your breakpoint. VSCode and Visual Studio both make this as easy as pie. Need to disable? Right-click and toggle it off.

Stepping Through Code with Step-In, Step-Out, and Step-Over Commands

Hit F10 for Step Over. Skips over the function execution. F11 for Step Into. Dives you right into the function details. Shift+F11? That’s your Step Out. Completes the function and returns to the caller.

Use these commands and navigate through your Python jungle with finesse.

Configuring Conditions and Actions for Breakpoints

Right-click the breakpoint in VSCode or Visual Studio. Set conditions to break only when certain criteria are met. Like, when a variable hits a specific value. You can also configure actions to log messages. Helps you track without halting the script’s execution.

Inspecting and Modifying Values During Debugging

Viewing and Editing Variables Using DataTips, Autos, Locals, and Watch Windows

Hover over variables to see DataTips. Instant preview. Over at Autos and Locals window? It lists variables in the current scope. Perfect for spotting anomalies.

Watch Window on steroids. Add variables, monitor at your fingertips.

Utilizing the Debug Console in VSCode for Advanced Data Inspection

Open the Debug Console. Type expressions or print variable values. Inspect and tweak on-the-fly. You can run snippets of code, making it easier to see how changes affect program flow. This console lets you peek and poke around efficiently during a debug session.

Handling Exceptions

Viewing and Managing Exceptions in Visual Studio’s Exception Settings

Under Debug > Windows > Exception Settings. Check/uncheck to break on specific exceptions. Configure custom exception types if standard ones don’t cut it. Manage and watch exceptions without breaking a sweat. It’s all about control.

Using Debug Console in VSCode to Monitor and Handle Exceptions

Encounter an error? The Debug Console in VSCode helps track it. Use try-except blocks in the console to handle it gracefully. Print out stack traces and messages to understand what went wrong. It’s essential for anyone wanting to learn how to debug Python in VSCode.

Advanced Debugging Configurations and Strategies

Command Line Debugging with Debugpy

Setting Up Debugpy and Attaching to Processes in VSCode

Got your terminal? Good.

Install debugpy with pip:

pip install debugpy

Now you’re ready. Start your Python script with debugpy attached:

python -m debugpy --listen 5678 your_script.py

Head over to VSCode. Open the command palette (Ctrl+Shift+P) and type Debug: Attach to. Point it to localhost:5678. Bam! You’re now hooked into your script, live.

Running Scripts with Debugpy for Remote or Network Debugging Scenarios

For remote debugging? You better believe it.

Ensure debugpy is ready on the remote server:

python -m debugpy --listen 0.0.0.0:5678 your_script.py

Open SSH or any remote access tool. Back in VSCode, repeat the attach process but this time, connect to your remote IP. Perfect for those networked setups or when your code resides on another machine.

Conditional Breakpoints and Logging Points

Configuring Conditional Breakpoints for Complex Debugging Scenarios

Right-click on a breakpoint in VSCode or Visual Studio. Set conditions, make them smart. Need it to trigger only when x > 10? Done. Debugging gets laser-focused, tackling tricky bugs with surgical precision.

Using Logging Points to Monitor Values Without Halting Program Execution

Add log messages without stopping the flow. Go to the breakpoint settings, choose Log Message. Insert your dynamic message, Value of x={x}. Logs pour into the console, giving real-time insights.

Remote Debugging and SSH Configurations

Setting Up SSH Tunnels and Remote Debugging in VSCode

SSH to your remote server. Secure and straightforward. Establish a tunnel:

ssh -L 5678:localhost:5678 user@remote

Now, VSCode can attach as if the remote script was local. Debug as you would normally, but your script runs on the remote host. Handy for cloud setups or remote machines.

Configuring launch.json for Remote Debugging in VSCode

Modify launch.json. Add a configuration like this:

{
    "name": "Remote Attach",
    "type": "python",
    "request": "attach",
    "host": "localhost",
    "port": 5678
}

Extensions and Enhancements for Debugging in VSCode

Key Extensions for Improved Debugging Workflow

Overview of Essential Extensions, Including Pylint, Flake8, and Black for Linting and Formatting

Open VSCode. Head to the Extensions panel.

Pylint? It’s your code’s best friend, finding those elusive errors and enforcing coding standards.

Flake8? Think of it as Pylint’s twin with a different flair. Sometimes, one gets what the other misses.

Black? Your friendly formatter. One click, and your code’s appearance steps up a notch. There’s no syntax error escaping its watchful eye.

IntelliSense Features and Enhancements for Code Completion with Jedi and Black

IntelliSense isn’t just for code completion. It’s your coding GPS. With Jedi, it predicts your needs, suggesting functions, methods, and more without breaking a sweat.

Pair this with Black. It wraps up everything beautifully the moment you save. Now, that’s code completion and formatting working in harmony.

Leveraging Integrated Linting and Code Formatting Tools

Setting Up Linting and Formatting Tools to Maintain Code Quality

Let’s get everything set up.

Install Pylint and Flake8. They work out of the box, but a little customization never hurts. Go to your user settings:

"python.linting.pylintEnabled": true,
"python.linting.flake8Enabled": true,
"python.linting.enabled": true

Now, for Black:

"python.formatting.blackArgs": ["--line-length", "80"],
"python.formatting.provider": "black"

Activate, and they’re good to go. Your code quality just skyrocketed.

Benefits of Black, Pylint, and Flake8 Extensions for Streamlined Debugging

Clean code is easier to debug. Period.

Black keeps your code tidy. Pylint and Flake8 catch errors before they become bugs. Integrating these tools means fewer syntax errors and more structured code. It’s like having a safety net, ensuring your code stays robust.

So, want to know how to debug Python in VSCode? Start with these extensions. They’re the unsung heroes of debugging, letting you catch errors early, format code on the fly, and keep everything polished. Best part? All within the same charming interface of VSCode.

Troubleshooting Debugging Issues in Visual Studio Environments

Common Debugging Issues and Solutions

Resolving Breakpoint Errors and Inactive Breakpoints

Breakpoints not working? Frustrating, right?

First, check if you’re on the right Python interpreter. Sometimes, VSCode or Visual Studio points to a default path that’s not your virtual environment. Switch the interpreter.

Paths and Files: Ensure the script file path is correct. Relative paths can be sneaky.

Module Not Loaded: Set breakpoints AFTER the module loads. Use import statements rightly.

If breakpoints turn gray? Symbols not loaded. Compile your project if you’re in Visual Studio.

Environment Variables: Confirm paths to interpreters and libraries. Correct launch.json settings if needed.

Code Changes: Update breakpoints after substantial code edits. Refresh and try again.

Addressing Configuration Problems in launch.json or Project Settings

Editing the launch.json? Make sure the configuration matches your debug conditions.

{
    "name": "Python: Current File",
    "type": "python",
    "request": "launch",
    "program": "${file}",
    "console": "integratedTerminal"
}

Paths, filenames, variables. Triple-check these.

Integrated Terminal: Avoid external terminals. Keep debugging sessions inside VSCode.

Project Settings: In Visual Studio, manage through Solution Explorer. Right-click on your project, hit Properties, and adjust Debug settings.

Update paths for external libraries to match your debug environment. Misconfigs here lead to dead ends.

Environment and Package Compatibility Solutions

Ensuring Correct Environment Setup and Managing Dependencies

Virtual environments save your sanity. Activate using:

# Windows
env\Scripts\activate
# macOS/Linux
source env/bin/activate

Install dependencies:

pip install -r requirements.txt

Sync dependencies across different machines. Use exact versions to avoid heartbreaks.

Path Issues: Set up environment paths correctly to point to VSCode or Visual Studio. They need to detect the right Python interpreter. Use .venv folders inside the project for less hassle.

Steps to Troubleshoot Virtual Environment Issues in VSCode

Virtual environments misbehaving? Ensure they’re activated.

Check Python Path in:

{
    "python.pythonPath": "env/bin/python"
}

Mismatch in libraries? Reinstall globally unnecessary dependencies inside the venv:

pip uninstall <package>
pip install <package>

Update references for your project settings both in VSCode and Visual Studio. Correct paths in launch.json:

{
    "env": {
        "PYTHONPATH": "${workspaceFolder}/my_module"
    }
}

Manual activation?

# Windows
Set-ExecutionPolicy Unrestricted -Scope Process
. .\env\Scripts\Activate

VSCode Debug Console lets you manually tweak and test changes instantly.

FAQ on How To Debug Python In VSCode

How do I set up the Python debugger in VSCode?

To set up the Python debugger, first install the Python extension from the Extensions Marketplace. Open your Python script, click on the debug icon on the sidebar, and select “Run and Debug”. VSCode will create a launch.json file. Customize it as needed to define your debug configurations.

How do I add breakpoints in my Python code?

Adding breakpoints is straightforward: open your Python file in VSCode and click on the left margin next to the line number where you want to pause execution. You’ll see a red dot indicating the breakpoint. Press F5 to start debugging, and the code will stop at your breakpoints.

Can I use the integrated terminal while debugging Python in VSCode?

Yes, you can use the integrated terminal alongside the debugger. Open the terminal from the View menu or press Ctrl+`. It allows you to run commands, inspect variables, and interact with your Python environment while your code is paused at breakpoints.

What is launch.json, and how do I configure it?

launch.json is a configuration file where you define how the debugger launches your Python program. You can specify the Python interpreter, script arguments, workspace settings, and debugger options. This file is generated initially by VSCode but can be customized to fit your specific debugging needs.

How can I inspect variables during a debugging session?

When your code execution stops at a breakpoint, you can inspect variables using the Debug panel. Hover over a variable in the editor to see its value, or check the “Variables” section in the Debug sidebar. You can also add expressions to the “Watch” list to track their values.

What are exception breakpoints, and how do I use them?

Exception breakpoints are used to pause code execution when specific exceptions are thrown. To set them, go to the Debug sidebar, click on the breakpoints section, and select “Add Exception Breakpoint”. You can choose to break on all exceptions or just uncaught exceptions.

How do I navigate the call stack in VSCode?

During a debugging session, you can view the call stack in the Debug panel. The call stack shows the path your code took to get to the current breakpoint. Clicking on any frame in the call stack will navigate the editor to that specific point in your code.

Can I use conditional breakpoints in VSCode?

Yes, you can set conditional breakpoints that pause execution only when certain conditions are met. Right-click on an existing breakpoint and choose “Edit Breakpoint”. Enter an expression, and the debugger will only pause when this expression evaluates to true.

What is step-through debugging, and how do I perform it?

Step-through debugging allows you to execute your code line-by-line, inspecting the state after each step. Use the Debug Toolbar to step over a function (F10), step into a function (F11), or step out of a function (Shift+F11). This helps you understand the flow and identify issues.

How do I handle errors found during debug sessions in VSCode?

When you encounter errors during a debug session, the Debug Console is your friend. It displays error messages, stack traces, and allows interaction with the Python interpreter. Fix the error in your code, save the changes, and restart the debug session to see if the issue is resolved.

Conclusion

Wrapping up, how to debug Python in VSCode involves straightforward steps and essential tools. Start by installing the Python extension. Utilize breakpoints, inspect the call stack, and configure your launch.json file for optimal debugging. Use the integrated terminal and handle exceptions effectively with exception breakpoints.

Key Takeaways:

• Install the Python extension from the Extensions Marketplace.
• Set breakpoints by clicking next to line numbers.
• Configure the launch.json for tailored debugging sessions.
• Inspect variables and use the Debug Console for real-time information.
• Navigate and manage your call stack.
• Utilize conditional breakpoints for specific situations.

Now you should have a toolset ready for efficient debugging. Visual Studio Code is designed to make your Python development seamless and precise. Dig in, explore the tools, and debug with confidence.

• Author
• Recent Posts

Bogdan Sandu

Bogdan is a seasoned web designer and tech strategist, with a keen eye on emerging industry trends.

With over a decade in the tech field, Bogdan blends technical expertise with insights on business innovation in technology.

A regular contributor to TMS Outsource's blog, where you'll find sharp analyses on software development, tech business strategies, and global tech dynamics.

Latest posts by Bogdan Sandu (see all)

• How to Check Screen Time on iPhone - December 11, 2024
• How to Autoformat in VSCode Effortlessly - December 10, 2024
• How to Turn Off Restrictions on iPhone - December 10, 2024