AP CS A Project: The CSV Data Parser & Analyzer

1. Project Overview

In this project, you will bridge the gap between "plain text" and "structured data." You will write a Java program that reads a Comma Separated Values (CSV) file, transforms each row into a custom Object, and performs data analysis to find trends, leaders, or statistics.

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2. Sample Dataset: olympics_data.csv

Create a file named olympics_data.csv in your project's root folder and paste the following:

Athlete,Country,Gold,Silver,Bronze,Total
Léon Marchand,France,4,0,0,4
Torri Huske,USA,3,2,0,5
Mollie O'Callaghan,Australia,3,1,1,5
Simone Biles,USA,3,1,0,4
Summer McIntosh,Canada,3,1,0,4
Pan Zhanle,China,2,0,0,2
Sarah Sjostrom,Sweden,2,0,0,2
Rebeca Andrade,Brazil,1,2,1,4
Gabby Thomas,USA,3,0,0,3
Sifan Hassan,Netherlands,1,0,2,3
Carlos Yulo,Philippines,2,0,0,2
Katie Ledecky,USA,2,1,1,4

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3. The Weighted Score (In-Class Lab)

As a class, we will extend the Athlete class to include a Weighted Medal Score. This allows us to rank athletes based on the "quality" of medals rather than just the quantity.

The Formula:

• Gold: 3 points
• Silver: 2 points
• Bronze: 1 point

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4. Your Mission: Choose Your Data

After completing the Olympics demo, you must find (or create) your own CSV dataset. It must contain at least 3 columns of numeric data, 2 columns of text data, and at least 20 rows.

"Level Up" Options (Choose One):

1. The Filterer: Allow the user to input a specific category (e.g., a Team Name or Genre) and display only those records, followed by a count of how many matches were found.
2. The Statistician: For a specific numeric column, calculate and display:
   • Mean (Average)
   • Median (Middle value—requires sorting the list!)
   • Min & Max
   • Standard Deviation (The spread of your data)
3. The Comparative Analyzer: Load two separate CSV files (e.g., 2023_data.csv and 2024_data.csv). Identify which items appear in both files and calculate the percentage change in their numeric values.

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5. Troubleshooting Guide

• ArrayIndexOutOfBoundsException: You tried to access an index that doesn't exist. Check if your CSV has empty lines at the bottom or if a row is missing a comma.
• NumberFormatException: You tried to turn a word (like "Gold") into an int. Fix: Ensure you called fileReader.nextLine() once before your loop to skip the header row.
• File Not Found: Ensure your .csv file is in the root folder of your project (the main folder containing src), not tucked inside the src folder itself.

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6. Using AI to Clean Your Dataset

If you find great data on the web but it’s messy, use an AI to format it for your Java program. Use this prompt:

"I have raw data about [Your Topic]. I need a clean CSV file.

1. Use the header: [List your columns here]
2. Ensure every row has exactly the same number of commas.
3. Remove any internal commas in names (e.g., change 'Smith, John' to 'John Smith').
4. If a value is missing, put a 0.
5. Output only the CSV text."

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7. Advanced Pro-Tips

• The Delimiter: Not all "CSVs" use commas. If your data uses semicolons, change your code to line.split(";").
• Trimming: Sometimes CSVs have extra spaces (e.g., " USA"). Use data[1].trim() to remove leading/trailing whitespace before comparing Strings.
• Closing Resources: Always call fileReader.close() after your while loop to prevent memory leaks.

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8. Reflection Questions

Answer these in a Google Doc attached to the Google Classroom assignment

1. Why is Integer.parseInt() necessary when reading from a CSV file? Why can't we just assign the value directly?
2. What happens to your program if a row in the CSV is missing a piece of data? How could you make your code more "robust" to handle this?
3. Which "Level Up" did you choose, and what was the hardest logic error you faced?

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9. Grading Rubric (100 pts)

Criteria	Description	Points
Object Encapsulation	Class has private variables, constructor, and getters.	20
File Handling	Successfully uses File and Scanner with a try-catch.	15
Parsing Logic	Correct use of .split(",") and skips header row.	20
Data Conversion	Correct use of Integer.parseInt or Double.parseDouble.	15
Collections	Objects are stored and managed within an ArrayList.	15
Analysis/Level Up	Program performs a meaningful calculation, filter, or comparison.	15