**Course Title:** Modern Python Programming: Best Practices and Trends **Section Title:** File Handling and Working with External Data **Topic:** Reading and writing files (text, CSV, JSON) with Python **Overview** File handling is an essential aspect of programming, and Python provides an efficient and easy-to-use interface for working with files. In this topic, we will cover the basics of reading and writing files in Python, including text files, CSV files, and JSON files. **Reading Text Files** In Python, you can read a text file using the `open()` function in read mode (`'r'`). Here's an example: ```python with open('example.txt', 'r') as file: content = file.read() print(content) ``` The `with` statement is used to ensure that the file is properly closed after it is no longer needed. You can also read a file line by line using the `readlines()` method or a `for` loop: ```python with open('example.txt', 'r') as file: for line in file: print(line.strip()) ``` **Writing Text Files** To write to a text file, you can use the `open()` function in write mode (`'w'`). Here's an example: ```python with open('example.txt', 'w') as file: file.write('Hello, World!') ``` If you want to append to an existing file instead of overwriting it, you can use the append mode (`'a'`): ```python with open('example.txt', 'a') as file: file.write('Appended text.') ``` **Reading and Writing CSV Files** Python provides the `csv` module for working with CSV files. You can use the `reader` and `writer` classes to read and write CSV files: ```python import csv with open('example.csv', 'r') as file: reader = csv.reader(file) for row in reader: print(row) ``` ```python import csv with open('example.csv', 'w') as file: writer = csv.writer(file) writer.writerow(['Name', 'Age']) writer.writerow(['John Doe', 30]) ``` **Reading and Writing JSON Files** Python provides the `json` module for working with JSON files. You can use the `dump()` and `load()` functions to write and read JSON files: ```python import json data = {'name': 'John Doe', 'age': 30} with open('example.json', 'w') as file: json.dump(data, file) ``` ```python import json with open('example.json', 'r') as file: data = json.load(file) print(data) ``` **Key Concepts** * Use the `with` statement to ensure that files are properly closed after use. * Use the `open()` function to read and write files in different modes (e.g., `'r'`, `'w'`, `'a'`). * Use the `csv` module for working with CSV files. * Use the `json` module for working with JSON files. **Best Practices** * Always close files after use to prevent file descriptor leaks. * Use the `with` statement to ensure that files are properly closed after use. * Use the `try`-`except` block to handle file-related errors. **Additional Resources** * [Python documentation: Input and Output](https://docs.python.org/3/tutorial/inputoutput.html) * [Python documentation: csv module](https://docs.python.org/3/library/csv.html) * [Python documentation: json module](https://docs.python.org/3/library/json.html) **Exercise** 1. Create a text file called `example.txt` and write a program to read and print its contents. 2. Create a CSV file called `example.csv` and write a program to read and print its contents. 3. Create a JSON file called `example.json` and write a program to read and print its contents. **Leave a Comment or Ask for Help** If you have any questions or need further clarification on this topic, please leave a comment below. If you'd like to discuss this topic further or get help with the exercise, please ask, and we'll be happy to assist you. In the next topic, we will cover the basics of Python’s `pathlib` and `os` modules for file manipulation.