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{"@context":"https://schema.org","@type":"Article","name":"How to Build a Python Script: A Beginner’s Guide to Python Scripting","headline":"How to Build a Python Script: A Beginner’s Guide to Python Scripting","abstract":"Learn scripting and how to build Python scripts from scratch. Set up your environment, structure your code, run the script, and explore real examples with tips to get started.","description":"Learn scripting and how to build Python scripts from scratch. Set up your environment, structure your code, run the script, and explore real examples with tips to get started.","articleBody":"## What is a Python script? \n\n**Scripting** refers to writing small programs called “scripts” to automate tasks, manipulate data, or control other programs. A **Python script** is a `.py` file containing a sequence of instructions in the Python [programming](/article/what-is-programming) language that are executed line by line by an interpreter. \n\nUnlike compiled languages (such as C++ or Java), which require code to be transformed into machine language before running, scripting languages like Python are interpreted directly. This makes them ideal for quick development and automation. \n\n**Benefits of scripts:** \n\n- **Automation:** Scripts are great for automating repetitive tasks like renaming files, scraping data, or sending emails. \n- **Simplicity:** Scripts are often easier to write, understand, and modify than full-scale applications. \n- **Flexibility:** You can quickly test and run parts of your code without compiling it. \n\nThink of scripting as giving your computer a to-do list—and Python is the language you use to write that list. \n\nNow that we understand scripting and why it’s useful, let’s prepare our system to write and run Python scripts. \n\n\n## Setting up the environment to create a Python script \n\nBefore writing our first Python script, we need a few tools in place: Python, a code editor, and a space to store the project. \n\n### Install Python \n\nPython needs to be installed on our computer to run scripts. If you haven’t installed it, follow our step-by-step instructions on the [Installing Python 3 and Python Packages](https://www.codecademy.com/article/install-python3) article. \n\n### Install Visual Studio Code \n\nWhile we can use any text editor to write scripts, a dedicated code editor like Visual Studio Code (VS Code) makes it easier with features like syntax highlighting and debugging tools. Check out our [Getting Started with Visual Studio Code](https://www.codecademy.com/article/visual-studio-code-setup) article to get started. \n\n### Create a project folder and script file \n\nOnce Python and the editor are ready, it's time to organize our workspace: \n\n- **Create a Folder:** Make a new folder for your Python projects on your computer. You can name it something like `python-scripts`. \n\n- Create a Python File: Inside this new folder, create a file and name it something like `rename_files.py`. \n\nHere’s an example of what our folder structure should look like \n\n```plaintext \npython-scripts/ \n├── rename_files.py      # Your main Python script file \n└── README.md            # Optional: A file to describe your project \n``` \n\nWe're just about ready to start writing our scripts, but before we dive in, let's go over the basic structure of a script. \n\n## Structure of a Python script \n\nBefore diving into writing the code, it's essential to understand the basic structure of a Python script. A well-organized script will be easier to write, debug, and maintain. \n\n### Inserting the shebang line \n\nYou can add a shebang at the top of your script on Unix-based systems like macOS or Linux. The shebang tells the system which interpreter to use when running the script. \n\n**Example:** \n\n```py \n#!/usr/bin/env python3 \n``` \n\nThis line is optional for Windows users, but it’s a good practice to include it if you're working in a cross-platform environment. \n\n### Importing modules \n\nPython allows us to import pre-written code (called modules) to extend the functionality of our script. These can be built-in Python modules or external libraries you’ve installed. \n\nFor example, if we want to work with dates and times, we can import the `datetime` module: \n\n```py \nimport datetime \n``` \n\nWe can also import specific functions from a module: \n\n```py \nfrom datetime import datetime \n``` \n\n### Defining functions \n\nFunctions organize our code into reusable blocks. In Python, functions are defined using the `def` keyword. \n\n**Example:** \n\n```py \ndef greet(name): \n  return f"Hello, {name}!" \n``` \n\n### Main program block \n\nIn Python, it’s common to include a special `if __name__ == "__main__":` block to run our script only when executed directly, not when imported as a module into another script. \n\n**Example:** \n\n```py \nif __name__ == "__main__": \n  print("This script is running directly!") \n``` \n\n### Code execution \n\nOnce we’ve written the code, we can run the script from our terminal or editor. The code inside the `if __name__ == "__main__":` block will execute when the script is run directly. \n\nThis structure is the foundation of most Python scripts. Let's build our first Python script by combining all these concepts in an example! \n\n## Building our first Python script \n\nLet us build a Python script that automates a task: renaming files in a folder. This script will allow us to quickly rename multiple files with a standardized naming pattern, saving time and effort. Open the `rename_files.py` file we had created earlier, and paste this code into it: \n\n```py \nimport os \n\n# This function renames all files in the given folder using a consistent naming pattern \ndef rename_files_in_directory(directory, name_prefix="renamed_file", file_extension=".txt"):  \n  try:  \n    files = os.listdir(directory) # Get all files in the directory \n    for i, filename in enumerate(files): \n      new_name = f"{name_prefix}_{i+1}{file_extension}"    # Create a new name \n      old_path = os.path.join(directory, filename)         # Full path to the original file \n      new_path = os.path.join(directory, new_name)         # Full path to the new file \n      os.rename(old_path, new_path)                        # Rename the file \n      print(f"Renamed: {filename} -> {new_name}") \n \n  except FileNotFoundError: \n    print("Directory not found. Please check the path.") \n \n  except Exception as e: \n    print(f"An error occurred: {e}") \n  \n# Main program block - this runs only when the script is executed directly \n if __name__ == "__main__":  \n   folder_path = "your/folder/path/here"     # Replace with your actual folder path \n   rename_files_in_directory(folder_path) \n```` \n\nIn this script: \n\n- We import the [`os`](https://www.codecademy.com/resources/docs/python/os-path-module) module to work with folders and files on your computer. \n- The function `rename_files_in_directory()`: \n  - Takes a folder path. \n  - Loops through all the files in it. \n  - Renames each file using a pattern like `renamed_file_1.txt`, `renamed_file_2.txt`, etc. \n- The main block at the bottom runs the function only when we run the script directly. \n\nWe need to update the folder path, save the file, and run the script to rename our files. \n\nNow that we've built our first Python script, let’s walk through how to run a Python script from the terminal or code editor. \n\n## How to run a Python script? \n\nOnce you’ve written and saved your script, it’s time to execute it. Here's how you can run a Python script in a few ways: \n\n### Run the Python script from the terminal\n\nTo run the Python script using the [terminal](https://www.codecademy.com/resources/docs/command-line/terminal), follow the steps as mentioned: \n\n- Open terminal (command prompt or shell) and navigate to your project folder \n- Use the `cd` command to move into the folder where your `.py` file is saved: \n\n```bash \ncd path/to/your/project-folder \n``` \n\n- Run the Python script using this command: \n\n```bash \npython rename_files.py \n``` \n\n> **Note:** Use `python` or  `python3` depending on your setup. \n\n\n### Run the Python script on Visual Studio Code \n\nTo run the Python script on Visual Studio Code, click on the run button at the top right, or use the shortcut keys:  \n\n**On windows:** <kbd>Ctrl</kbd> + <kbd>F5</kbd> \n\n**On macOS:** <kbd>Cmd</kbd> + <kbd>F5</kbd> \n\nWe’ll see the output in the Terminal panel at the bottom. \n\n \nOnce the script runs, it will rename all the files in the target folder, and we’ll see messages printed for each renamed file. \n\nWe've built and successfully run our first Python script! Next, explore a few best practices to help us write better Python scripts. \n\n\n## Best practices for writing Python scripts \n\nWhether working on a small task or building something big, following good practices makes our code easier to understand, debug, and share. Here is a list of some of them: \n\n### Use meaningful variable and function names \n\nAvoid using vague names like `x` or `temp` (unless appropriate). Instead, choose names that describe what the value or function does. Instead of creating a function as follows: \n\n```py \ndef fn(a): \n  return a * a \n``` \n\nCreate a function with an understandable name: \n\n```py \ndef square_number(number): \n  return number * number \n``` \n\n### Add comments and docstrings \n\nUse comments to explain complex or essential parts of your code. Add docstrings at the beginning of functions to describe what they do and what arguments they expect. \n\n```py \n# Calculates the area of a rectangle  \ndef calculate_area(length, width):  \n  """Returns the area given length and width."""  \n  return length * width \n``` \n\n### Follow the PEP 8 style guide \n\n[PEP 8](https://peps.python.org/pep-0008/) is Python’s official style guide. It covers: \n\n- Naming conventions \n- Indentation (4 spaces) \n- Line length (max 79 characters) \n- Spacing and blank lines \n\nMost code editors like VS Code highlight PEP 8 issues automatically. \n\n### Organize code into functions or modules \n\nBreak large scripts into smaller functions to avoid repetition. For very long scripts, consider splitting the code across multiple modules (files) and importing them. \n\n```py \n# In utils.py \ndef greet(name):  \n  return f"Hello, {name}!" \n\n# In main.py \nfrom utils import greet  \nprint(greet("Alice")) \n``` \n\nFollowing these practices early in the learning journey builds a strong foundation for writing clean and maintainable code, essential for individual projects and team-based development. \n\n## Conclusion \n\nIn this article, we explored how to build Python scripts from scratch. From understanding what scripting means, setting up the environment, writing and running a script, to learning best practices, each step helps build confidence and clarity in automating tasks with Python. \n\nTo expand your knowledge of Python's core concepts like variables, functions, and control flow, check out the [Learn Python 3](https://www.codecademy.com/enrolled/courses/learn-python-3) course on Codecademy. It’s a great next step to strengthen your skills and take on more advanced scripting projects. \n\n## Frequently asked questions \n\n### 1. How do I compile a Python script? \n\nYou don’t need to manually compile Python scripts like in other programming languages. Python is an interpreted language, which means you just run the script using the command: \n\n```py \npython script_name.py  \n``` \n\n### 2. What is the Python script format? \n\nA Python script is a plain text file with a `.py` extension. It contains Python code written using proper indentation and syntax. A typical script might include: \n\n- Imports \n- Functions \n- Conditional statements \n- A main block (`if __name__ == "__main__":`) \n\n### 3. Is Python a scripting language? \n\nYes, Python is considered a scripting language because it’s often used to automate tasks, write small programs, and quickly build prototypes. It’s also a general-purpose programming language used for [web development](https://www.codecademy.com/resources/blog/what-is-web-development/), [data science](https://www.codecademy.com/resources/blog/what-is-data-science/), [AI](https://www.codecademy.com/resources/docs/ai), and more. \n\n### 4. What is `__init__` in Python? \n\n`__init__` is a special method in Python classes. It runs automatically when a new object is created and is used to initialize the object’s attributes. \n\n\n### 5. What is the `main()` function in Python? \n\nPython doesn’t require a `main()` function like other languages, but defining one for clarity is a common practice. The standard way to run the main logic is: \n\n```py \nif __name__ == "__main__":  \n  main() \n``` \n\nThis block ensures your script runs only directly executed, not when imported as a module. \n","wordCount":1766,"author":{"@type":"Organization","name":"Codecademy","sameAs":"https://www.codecademy.com/"},"publisher":{"@type":"Organization","name":"Codecademy","sameAs":"https://www.codecademy.com/"}}