How to Open Python .py Files in IDLE with a Doubleclick?

I love tweaking my coding workflow. Small improvements accumulate over time and can lead to a massive productivity increase. Today, I caught myself being annoyed that I always needed to spend three clicks or so just to open a Python file in IDLE, the default Python editor on Windows. Time to change that!

Do you want to open Python files in Windows by just double-clicking on them? Make the IDLE the default editor for Python files in a few simple steps:

1. Right-click a Python file, select Properties, and locate the “Opens with” section.
2. Click the Change button.
3. Select More Apps, scroll down, and click the text Look for another app on this PC.
4. Find your Python installation path by running import sys; print(sys.executable) in your Python script.
5. Navigate to the Lib/idlelib/ path and select the file idle.bat.
6. Click Open and OK to close the Properties Window.

Congratulations! You can now open Python .py file in IDLE by double-clicking on them. ?

I’ve created a gif to help you nagivate through those steps—but be careful: it’s on my German Windows machine so you may see some strange-looking text snippets:

You can find a slightly more detailed guide on IDLE basics in the following:

IDLE Best Practices and Starter’s Guide

IDLE, which stands for Integrated DeveLopment Environment, is a lightweight IDE that comes pre-installed with Python and is specifically designed for Python development. It is an excellent choice for beginners as it offers a simple and clean interface, allowing users to focus on learning and writing Python code without being overwhelmed by complex features.

To open a Python file in IDLE on Windows, you can either set IDLE as the default program to open Python files or open a Python file directly in IDLE.

Setting IDLE as the default program is useful if you plan on using IDLE regularly for your Python development needs. This can be done by right-clicking on any Python file, selecting “Open with,” choosing the default program, and browsing to the idle.bat file located in the idlelib folder of your Python installation directory.

On the other hand, if you prefer to open your Python files directly in IDLE, simply launch IDLE, click the “File” menu, and select “Open.” This will allow you to browse your file system and open the desired Python file in IDLE.

Once your Python file is open in IDLE, you can edit your code, save your changes, and run your program using the “Run” menu or by pressing the F5 key on your keyboard source.

Installing and Setting Up IDLE on Windows

Downloading Python and IDLE

Before you can start using IDLE to work with Python files, you need to have Python and IDLE installed on your Windows machine. You can download the latest version of Python for Windows from the official Python website. The installation package includes IDLE, making it easy to get started.

If you are using a Python distribution such as Anaconda, IDLE is not included by default. However, you can install it using a command within the Anaconda Prompt:

conda install -c anaconda idle

Once the installation is complete, you can find IDLE listed under Python in the Start menu.

Setting Environment Variables

To make it easier to use Python and IDLE, you should set up environment variables in Windows. This will enable you to run Python and IDLE from the command prompt without providing the full path.

1. Go to the Windows System Properties by right-clicking on the Computer/This PC icon on the Desktop or in the Start menu, then selecting ‘Properties’.
2. Click on ‘Advanced system settings’ to open the ‘System Properties’ window.
3. Navigate to the ‘Advanced’ tab and click on ‘Environment Variables’.
4. Locate the ‘Path’ variable in the ‘System variables’ section, then click ‘Edit’.
5. Add the following paths to the ‘Path’ variable, separated by semicolons:
   • The location of python.exe – typically found in C:\Python<version>. For example, C:\Python39 for Python 3.9.
   • The location of pythonw.exe – typically found in the same folder as python.exe.
   • The location of the Scripts folder – usually located at C:\Python<version>\Scripts.
6. Click ‘OK’ to save your changes, and then close any remaining windows.

Now you should be able to run Python and IDLE directly from the command prompt, as well as easily open Python files in IDLE by right-clicking on them and choosing “Open with IDLE”.

Opening Python Files in IDLE on Windows

This section will discuss two methods for opening Python files in IDLE: Using the Right-Click Method and Running Files via Command Line.

Using the Right-Click Method

To open a .py file with the IDLE IDE, navigate to the folder containing the file, then follow these steps:

1. Right-click on the .py file
2. Select “Open with”
3. Choose “Choose default program” or “Choose another app”
4. Click “Browse”
5. Navigate to C:\PythonXX\Lib\idlelib (replace XX with your Python version)
6. Select idle.bat and click “Open”

Now, double-clicking a Python file will open it in the IDLE IDE for editing. If you want to run the script, press F5 on your keyboard or select “Run” → “Run Module” from the menu bar. The Python interpreter will restart, and the script will run in IDLE.

Running Files via Command Line

For those who prefer using the command line, you can also open Python files in IDLE by following these steps:

1. Press Win + R on your keyboard to open the “Run” window
2. Type cmd and press Enter to open the Command Prompt
3. Navigate to the folder containing the .py file using the cd command (e.g., cd C:\Users\YourUsername\Documents\MyPythonScripts)
4. Type idle your_script.py (replace your_script.py with the name of your Python file) and press Enter

This will open the .py file in the IDLE IDE for editing.

To run the script, use the same method mentioned in the previous sub-section: press F5 on your keyboard or select “Run” → “Run Module” from the menu bar. The Python interpreter will restart, and the script will run within the IDLE shell.

IDLE Interface Overview

This section will give you an overview of the IDLE interface and its features.

Code Editing Window

The code editing window in IDLE allows you to write and edit Python code with syntax highlighting.

Although I have switched them off, the default editing window also includes line numbers, which can help you navigate through your code and identify the location of errors.

Some other functionalities of the code editing window are:

• Undo and redo options
• Smart indentation
• Auto-formatting
• Parenthesis matching

IDLE Shell

The IDLE shell is a REPL (Read Evaluate Print Loop) environment that allows you to run Python code interactively.

You can use the shell window to test your code, run Python tutorials, or explore Python features. The shell provides instant feedback on code execution and makes it easy to debug and understand your code.

Some aspects of the Python shell are:

• Syntax coloring
• Command history
• Autocompletion of Python keywords and function names
• Ability to run code snippets from the code editing window directly in the shell

Debugger

IDLE also comes with a built-in debugger, which is useful for diagnosing issues in your Python code. The debugger allows you to set breakpoints, step through your code, and inspect the values of variables at any point during execution. Some of the features of the IDLE debugger include:

• Setting and clearing breakpoints
• Stepping through code line by line
• Inspecting the call stack
• Viewing the state of local and global variables

Overall, the IDLE interface provides a user-friendly environment to write Python code and debug it efficiently.

Configuring IDLE for Python Files

Associating File Types with IDLE

To set up IDLE as the default editor for your Python files on Windows, you need to associate the .py and .pyw file types with the IDLE program.

To do this, right-click on your Python file and navigate to ‘Properties‘.

In the ‘Opens with‘ section, click the ‘Change...‘ button and select IDLE from the list of programs.

If IDLE is not shown, click on ‘More apps’ and find it in the list or browse to the location of the idle.bat file, which is typically found inside the PythonXX\Lib\idlelib folder, where XX represents your Python version.

Make sure to check the box for “Always use the selected program to open this kind of file” before confirming your selection.

Customizing IDLE Editor Settings

IDLE (Integrated Development and Learning Environment) is an interactive interpreter for Python that comes with a range of useful features, such as code completion and automatic indentation.

To customize IDLE’s settings for a more personalized editing experience, simply open the IDLE editor and navigate to ‘Options‘ > ‘Configure IDLE‘.

In the configuration window, you can adjust various settings, such as:

• Fonts: Change the font size, style, and color for better readability.
• Indentation: Set the number of spaces used for automatic indentation.
• Keybinding: Customize the keyboard shortcuts for specific actions.
• Extensions: Manage the extensions available in IDLE to expand its functionality.

Be sure to click ‘Apply‘ after making any changes and restart the IDLE shell to see the updated settings in action. By configuring IDLE to suit your preferences and associating file types, you’ll create a more efficient and customized coding environment.

For a more in-depth tutorial on using IDLE and its features, visit the Python documentation for IDLE.

Working with IDLE on Other Platforms

While IDLE is included by default with Python installations on Windows, it is also available for other platforms like macOS and Linux. This section will discuss how to work with IDLE on macOS and Linux.

IDLE on Mac

IDLE is included with the standard Python installation on macOS. To open IDLE on your Mac, first, locate the Python folder in the Applications directory. Within the Python folder, there should be an app named IDLE (or IDLE.app).

Double-click the app to launch IDLE, and you’re ready to start working with Python code.

If you prefer using Terminal, you can open IDLE by navigating to the /Applications/Python <version>/lib/idlelib/ directory and running the idle.bat file. Replace <version> with your installed Python version number.

For example:

cd /Applications/Python\ 3.8/lib/idlelib/
./idle.bat

IDLE on Linux

On Linux systems, you may need to install IDLE separately, depending on the Linux distribution and Python package you have installed. Check your package manager (e.g., apt for Ubuntu/Debian, yum for CentOS/RHEL, pacman for Arch) for the IDLE package, which is usually named idle or idle-python<version>.

Here’s an example for Debian-based systems:

sudo apt-get install idle-python3.8

Replace 3.8 with your desired Python version.

Once IDLE is installed, you can launch it by typing idle or idle<version> in the terminal, or you can find it in your desktop environment’s application menu.

When working with Python files, you might also want to set up IDLE as the default editor on Linux. To do this, follow these steps:

1. Right-click on a .py file.
2. Choose “Open with” or “Properties.”
3. Select “IDLE” from the list of available applications, or browse for the idle.bat file located in the /usr/lib/python<version>/lib/idlelib/ directory.

This completes the brief overview of using IDLE on macOS and Linux systems. Though the process may differ slightly across platforms, the core functionalities of IDLE remain consistent, allowing you to write and execute Python code efficiently.

Tips and Best Practices for using IDLE

One of the advantages of using IDLE as a Python development environment is its user-friendly interface and built-in features, which facilitate coding and debugging. To make the most of IDLE, follow these tips and best practices.

Reading and Working with Python Files

IDLE allows you to efficiently read and work with Python module files (.py). To open a Python file, click on the File menu and then Open. Once the file is open, you can perform various operations such as editing, running the module, or debugging. This guide shows that you can configure IDLE to open Python files by default, streamlining your workflow.

Code Completion and Call Tips

One valuable feature of IDLE is its autocompletion capabilities. IDLE will suggest completions for your code as you type, which helps reduce typing errors and speeds up the coding process. Similarly, call tips provide hints about function parameters as you type function calls, enhancing readability while coding.

Undo and Redo

IDLE provides an undo and redo functionality, which allows you to quickly revert or reapply changes made to your code. To access this feature, use the Edit menu or the corresponding keyboard shortcuts (Ctrl+Z for undo and Ctrl+Y for redo).

Running and Debugging Python Modules

One of the main features of IDLE is the ability to run Python module files as standalone programs. To execute a Python module, click on Run > Run Module or press the F5 key. If there are issues in your code, IDLE will highlight them in the interactive interpreter or the editor window, making debugging easier.

When actively debugging code, switch to DEBUG mode in IDLE’s interactive interpreter. This mode provides additional debug functionalities, like setting breakpoints and step-by-step execution of your code. Using DEBUG mode helps you identify and fix errors or exceptions more efficiently.

By following these best practices, you can enhance your productivity and make your experience using Python IDLE more enjoyable. Remember to always save your program files before running or debugging them to avoid data loss.

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