Getting Started

Running Python on Your Computer

To start coding in Python, you need to have Python installed on your computer. Follow the installation guide on our Installation Page if you haven’t done so already.

Once Python is installed, you can run Python code in several ways. Pick the one that fits what you are doing.

Diagram:

diagram ways to run Python mermaid

  graph TD
    A[Write Python code] --> B[Interactive shell / REPL]
    A --> C[Run a .py file]
    A --> D[One-liner with -c]
    A --> E[IDE Run button]
    B --> F[Output]
    C --> F
    D --> F
    E --> F

Different ways to execute Python code

Method	Best for
Interactive shell (REPL)	Quick experiments, testing one expression
Running a .py file	Real programs and scripts
python -c "code"	A throwaway one-liner from the terminal
IDE / editor Run button	Day-to-day development

Using the Command Line or Terminal

1. Open the Command Line (Windows) or Terminal (macOS/Linux):

   • Windows: Press Win + R, type cmd, and press Enter.
   • macOS/Linux: Use the terminal application.

2. Navigate to Your Python File’s Directory: Use the cd command to navigate to the directory where your Python file is located. For example:

   command

   cd path/to/your/python/files

3. Run Your Python Script: Execute your Python script using the python command followed by the filename with the .py extension.

   command

   python your_script.py

Creating Your First Python File

1. Open a Text Editor: Use a text editor (e.g., Visual Studio Code, Sublime Text, or Notepad) to write your Python code.

2. Write Your Python Code: Create a simple Python script, for example, a “Hello, World!” program:

   main.py

   # hello_world.py
   print("Hello, World!")

3. Save the File: Save the file with a .py extension, such as hello_world.py.

4. Run Your Python Script: Follow the steps mentioned above to navigate to the file’s directory in the command line or terminal and run the script.

Tip

Naming .py files: use lowercase letters and underscores (hello_world.py, data_loader.py). Avoid spaces, and never name a file after a standard library module (e.g. random.py or math.py) — doing so shadows the real module and causes confusing import errors.

Running a One-Liner

For a quick test you do not even need a file. The -c flag runs a string of code directly:

command

C:\Users\Your Name> python -c "print(2 ** 10)"
1024

Running a Module

The -m flag runs an installed module as a script. This is how you start common tools:

command

python -m venv venv          # create a virtual environment
python -m pip install requests
python -m http.server        # start a quick local web server

Important Python Commands

Interactive Mode

Python comes with an interactive mode that allows you to execute Python commands line by line.

• Open Interactive Mode:

command

C:\Users\Your Name>python
Python 3.11.2 (tags/v3.11.2:878ead1, Feb  7 2023, 16:38:35) [MSC v.1934 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello, World!")
Hello, World!

Note

You can also use the py command to open interactive mode:

command

C:\Users\Your Name>py
Python 3.11.2 (tags/v3.11.2:878ead1, Feb  7 2023, 16:38:35) [MSC v.1934 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello, World!")
Hello, World!

• Exit Interactive Mode:

command

C:\Users\Your Name>python
Python 3.11.2 (tags/v3.11.2:878ead1, Feb  7 2023, 16:38:35) [MSC v.1934 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello, World!")
Hello, World!
>>> exit()
C:\Users\Your Name>

Note

You can also leave the shell with a keyboard shortcut: Ctrl + Z then Enter on Windows, or Ctrl + D on macOS/Linux. Both do the same thing as exit().

Running a Python File

• Run a Python Script:

  command

  python your_script.py

Virtual Environment

Virtual environments help manage dependencies for different projects.

• Create a Virtual Environment:

  command

  python -m venv venv

• Activate Virtual Environment:

  • Windows:

    command

    .\venv\Scripts\activate

  • macOS/Linux:

    command

    source venv/bin/activate

• Deactivate Virtual Environment:

  command

  deactivate

Package Management (pip)

pip is the package installer for Python.

• Install a Package:

  command

  pip install package_name

• Install from Requirements File:

  command

  pip install -r requirements.txt

This should give you a solid start on running Python code, creating files, and using some essential commands. Explore more with our tutorials on Python Central Hub!

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Try it: Hands-on Exercises

Exercise 1 – Hello, World!

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Exercise 2 – Print Your Name

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Exercise 3 – Run a Simple Script

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