CHAPTER 1
Getting Started

When you began your Python development journey, you were most likely introduced to Python's Integrated Development and Learning Environment (IDLE). IDLE's simplicity is ideal for newcomers but leaves much to be desired by those who are more comfortable with the language and are in need of an efficient and productive workflow. A range of code editors and integrated development environments (IDEs) are available for Python development-some for general development with multilanguage support (such as Atom or Sublime) and others built exclusively for Python (such as PyCharm). Selecting a development environment is a matter of personal preference. As an experienced programmer, you might have already tried a few editors and thus are aware of what features you most desire. If you're in need of an extensible code editor that provides ample flexibility, efficiency, and productivity for managing Python source code, then Visual Studio Code is well worth your consideration.

Visual Studio Code (also referred to as VS Code) is a free, open-source, and cross-platform code editor developed by Microsoft. Ranked as the Most Popular Development Environment in the 2019 Stack Overflow Developer Survey, Visual Studio Code is a feature-rich highly customizable code editor that not only is great for editing source code but has built-in support for collaboration and cloud-hosted environments. Visual Studio Code's source code is available in the product's GitHub repository at github.com/microsoft/vscode. You're welcome to contribute to the project and can also view the product roadmap within the repository. Visual Studio Code is updated monthly with new features and bug fixes. For early adopters, the VS Code Insiders build provides a new build at least every day with features and bug fixes.

Visual Studio Code has built-in support only for JavaScript, TypeScript, HTML, and CSS, but it supports many additional languages, such as Python, through extensions. Before you begin programming in Python, you must install the extension. You can then begin to familiarize yourself with the editor's interface within the context of Python.

Installing Visual Studio Code

As a free, cross-platform code editor, Visual Studio Code runs on macOS, Linux, and Windows. Download Visual Studio Code from code.visualstudio.com. If the browser doesn't detect your operating system, visit code.visualstudio.com/#alt-downloads for more options. Platform-specific installation steps are available at code.visualstudio.com/docs/setup/setup-overview. Both macOS and Windows provide the option to add Visual Studio Code to your PATH environment variable. Adding Visual Studio Code to your PATH environment variable provides the convenience of opening a folder directly from the console using the command code <folder> or code. (to open the current folder).

As mentioned, Microsoft releases a new version of Visual Studio Code often with new features and important bug fixes. If your platform supports auto-updating, Visual Studio Code prompts you to install the new release when it becomes available. As an alternative, you can manually check for updates by running Help ? Check For Updates on Linux and Windows or by running Code ? Check For Updates on macOS.

NOTE If you're interested in trying the VS Code Insiders build, you can download a copy from code.visualstudio.com/insiders/. You can install the Insiders build side by side with the latest monthly build, which enables you to use both versions of the code editor independently.

The Visual Studio Code User Interface

Visual Studio Code's user interface (UI) provides a simple minimal layout that keeps your source code as the focus of the development environment. When you first start Visual Studio Code, it displays a default layout. Each time you start Visual Studio Code going forward, the editor opens in the same state it was in when last closed.

You can make yourself at home by customizing the layout to your liking. However, before you start moving things around, you should get to know the main areas of the UI and their respective function (see Figure 1.1).

Figure 1.1: The Visual Studio Code user interface.

Activity Bar

The Activity Bar, located on the far-left side, lets you switch between views. Views provide quick access to common tasks such as the following:

• Explorer-File and folder management
• Search-Global search and replace across open folders using plain text or regular expressions
• Source Control-Git source control for maintaining code repositories
• Run-Features used during debugging, such as variables, call stacks, and breakpoints
• Extensions-Browsing, installation, and management of extensions from the Extension Marketplace

In addition to the default views, the Activity Bar can also include custom views provided by extensions that you install from the Extension Marketplace. Each view has an icon that reflects its respective function.

You can reorder views by dragging and dropping them in the Activity Bar. Views can also be hidden if you right-click the view and select Hide From Activity Bar. Views are part of your custom layout that is preserved each time you run Visual Studio Code.

Side Bar

The Side Bar, located to the right of the Activity Bar, displays the active view. If no view is selected, the Side Bar is collapsed. You can resize the Side Bar by clicking and dragging the edge that it shares with the editor. The default views for the Side Bar are Explorer, Search, Source Control, Run, and Extensions (see Figures 1.2 through 1.6, respectively).

Figure 1.2: Explorer view.

Figure 1.3: Search view.

Figure 1.4: Source Control view.

Figure 1.5: Run view.

Figure 1.6: Extensions view.

Editor

The editor, which fills most of the screen, is where you edit files. You can resize the editor by clicking and dragging the edges that it shares with the Side Bar and the panels.

The top editor region can change depending on the type of file that's active in the editor. For example, if you edit a Markdown file, a Preview icon appears, thus enabling Visual Studio Code's Markdown Preview (see Figure 1.7).

Figure 1.7: In the top image, the Preview icon appears in the top editor region since a Markdown file is opened. Clicking the icon displays a preview of the Markdown file, as shown in the bottom image.

When you open a Python file, you instead see a Run Python File In Terminal icon (displayed as a Play button) in the top editor region. (The Run Python File In Terminal icon is a quick way for you to run a Python program.) When selected, a terminal opens, and the Python file is run (see Figure 1.8).

Figure 1.8: The Run Python File In Terminal icon displays at the top of the editor region. Clicking the icon runs the Python file.

For most file types, the top editor region also includes an Open Changes icon for viewing changes in the file since the last commit to source control (see Figure 1.9). Selecting the icon opens the Diffs editor (see Figure 1.10). The Diffs editor opens in a new tab with a side-by-side view of the diffs. You could also access the Diffs editor by selecting the file in the Source Control view.

Figure 1.9: When the Open Changes icon is clicked, a new tab opens that shows the diffs for the file.

Figure 1.10: The Diffs editor shows the changes made in the file since the last commit.

The region also contains a Split Editor Right icon for splitting the editor (see Figure 1.11). When selected, a new editor group opens to the right of the initial editor. You can open and modify files in either editor window.

Figure 1.11: When the Split Editor Right icon is clicked, a new editor group is opened to the right.

An opened and active file displays the source code in the middle of the editor, and a Minimap is located at the top right (see Figure 1.12). The Minimap provides a condensed miniature view of the entire file and is great for quick navigation and visually knowing where you are in the context of the entire file.

Figure 1.12: A Minimap displays at the right of the bankaccount.py file. You can click anywhere in the Minimap to quickly navigate to the code at that location.

You can open as many files as you like in the editor. Each opened file is distinguishable by a tabbed header. The active file is the file in which your cursor appears. You can drag tabs to reorder them and also pin tabs (Cmd+K Shift+Enter/Ctrl+K Shift+Enter1) to keep your most used files within reach. A pinned tab displays with the language icon for the respective file (see Figure 1.13).

Figure 1.13: The helloworld.py file is a pinned tab. A pin icon next to the filename in the tab indicates that...