Learning how to run programs written in Python is an essential skill for any developer. In this guide, we will explore the different ways you can execute Python programs, including interactive prompts and running Python code from files.

Running Python Programs Using Interactive Prompts

One way to run Python programs is by using interactive prompts. By opening your terminal and typing python, you can access the Python REPL (Read-Evaluate-Print-Loop). This interactive environment allows you to write and execute Python code immediately. For example, you can define variables and print their values. Simply type quit() to exit the Python REPL.

While the default Python REPL is useful, we recommend installing IPython for an enhanced command-line REPL experience. To install IPython, use the command pip install ipython. IPython provides features like syntax highlighting and code completion, making it a powerful tool for working with Python interactively.

Running Python Programs from Files

The second way to run a Python program is by saving your code into a file. Start by creating a new file, for example program.py, and write your Python code inside it. To run the program, open your terminal and use the command python program.py. When executing a Python program from a file, the entire code is executed as a whole, rather than one line at a time.

It’s a convention to save Python programs with the .py extension. This makes it easier to identify and execute Python files.

On Linux and macOS systems, you can transform a Python program into a shell script by adding a special line at the beginning of the file. This line indicates the executable to use to run the script. For example, if the Python executable is located at /usr/bin/python3, add the line #!/usr/bin/python3 at the top of the file. Then, set the execution permission on the file using the command chmod u+x program.py. Finally, you can run the program by typing ./program.py.

Using Integrated Development Environments (IDEs)

There are several IDEs that provide a convenient way to run Python programs. One popular choice is Visual Studio Code (VS Code) with the official Python extension from Microsoft. After installing the extension, you gain access to various features such as code autocompletion, error checking, formatting, and linting with pylint.

You can use the following commands within VS Code:

  • Python: Start REPL to run the REPL in the integrated terminal.
  • Python: Run Python File in Terminal to run the current file in the terminal.
  • Python: Run Current File in Python Interactive Window to run the current file in the interactive window.

To access these commands, open the command palette (View -> Command Palette, or Cmd-Shift-P) and search for “python”. This will display all the Python-related commands available in the IDE.

In conclusion, running Python programs can be done through interactive prompts or by executing code from files. Whether you prefer the Python REPL, a dedicated REPL like IPython, or using IDEs like VS Code, having a good understanding of these methods will greatly enhance your Python development experience.