**Course Title:** Modern Python Programming: Best Practices and Trends **Section Title:** File Handling and Working with External Data **Topic:** Build a script that processes data from files and external APIs.(Lab topic) **Prerequisites:** Before starting this lab, you should have a good understanding of Python basics, data structures, file handling, and working with external APIs. **Introduction:** In this lab, we will learn how to build a script that processes data from files and external APIs. This will involve reading data from various file formats (such as CSV, JSON, and text), as well as fetching data from external APIs. We will use the skills and knowledge gained from previous topics to develop a comprehensive script that demonstrates these concepts. **Reading Data from Files:** To start, let's revisit reading data from files. We will focus on CSV, JSON, and text files. ### CSV Files We can use the `csv` module to read data from CSV files. Here is an example: ```python import csv # Open the CSV file with open('data.csv', 'r') as file: # Create a CSV reader reader = csv.reader(file) # Iterate over the rows for row in reader: print(row) ``` ### JSON Files To read data from JSON files, we can use the `json` module. Here is an example: ```python import json # Open the JSON file with open('data.json', 'r') as file: # Load the JSON data data = json.load(file) # Print the data print(data) ``` ### Text Files We can use the `open` function to read data from text files. Here is an example: ```python # Open the text file with open('data.txt', 'r') as file: # Read the contents of the file contents = file.read() # Print the contents print(contents) ``` **Fetching Data from External APIs:** Next, we will learn how to fetch data from external APIs using the `requests` library. We will focus on GET requests. ```python import requests # Send a GET request response = requests.get('https://api.example.com/data') # Check if the request was successful if response.status_code == 200: # Get the JSON data data = response.json() # Print the data print(data) ``` **Building the Script:** Now that we have learned how to read data from files and fetch data from external APIs, let's build a script that combines these concepts. Our script will do the following: 1. Read data from a CSV file. 2. Fetch data from an external API. 3. Merge the data. 4. Write the merged data to a new CSV file. Here is the code: ```python import csv import requests import json # Step 1: Read data from a CSV file with open('data.csv', 'r') as file: reader = csv.reader(file) csv_data = [row for row in reader] # Step 2: Fetch data from an external API response = requests.get('https://api.example.com/data') if response.status_code == 200: api_data = response.json() # Step 3: Merge the data merged_data = csv_data + api_data # Step 4: Write the merged data to a new CSV file with open('merged_data.csv', 'w', newline='') as file: writer = csv.writer(file) for row in merged_data: writer.writerow(row) ``` **Conclusion:** In this lab, we have learned how to build a script that processes data from files and external APIs. We have combined our knowledge of reading data from files and fetching data from external APIs to develop a comprehensive script. By following this example, you can create your own scripts that process data from various sources. **Additional Resources:** * [requests library documentation](https://requests.readthedocs.io/en/master/) * [csv library documentation](https://docs.python.org/3/library/csv.html) * [json library documentation](https://docs.python.org/3/library/json.html) **Exercise:** Modify the script to handle errors and exceptions. For example, what if the CSV file does not exist? What if the API request fails? **Leave a comment or ask for help:** If you have any questions or need help with this lab, please leave a comment below. Next Topic: **Importance of testing in modern software development.**