Explore Data App

A Spring Boot web application for exploratory data analysis (EDA) of CSV files. Users can upload a CSV dataset (up to 10 MB), view comprehensive summary statistics, and generate distribution visualizations.

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Overview

Provides a quick, code‑free way to perform basic EDA on CSV files:

• Automated column profiling: Detects data type, calculates min, max, mean, median, mode, standard deviation, variance, count of non‑null values, and NA counts.
• Value distributions: Identifies unique value counts and top 5 most frequent values for categorical columns.
• Interactive plots: Generates histogram and box plot for numeric columns using Plotly.js.
• Configurable limits: File upload size and server port can be adjusted via application.properties.

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Example Visualization

Below is a sample output demonstrating how the app visualizes a column’s distribution:

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Features

• Upload CSV (≤ 10 MB) through a web form
• Summary report for each column: type, numeric stats, NA counts, unique values, top frequencies
• Column selector and interactive visualization (histogram & box plot)
• Error handling for oversized files and parsing issues
• Spring Boot DevTools for hot‑reload during development

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Tech Stack

• Java 21
• Spring Boot 3.3 (Web, Thymeleaf, DevTools)
• Apache Commons CSV 1.9.0
• Apache Commons Math3 3.6.1
• Plotly.js (loaded via CDN)
• Maven 3.6+ with Wrapper

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Getting Started

1. Clone the repository

   git clone https://github.com/emma‑lewis/explore-data-app.git
   cd explore-data-app

2. Build the project

   mvn clean package

3. Run the application

   • Using Maven:

     mvn spring-boot:run

   • Or with the packaged JAR:

     java -jar target/explore-data-app-0.0.1-SNAPSHOT.jar

4. Open in browser Navigate to http://localhost:8080 to upload your CSV and start exploring.

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Configuration

Modify src/main/resources/application.properties to adjust settings:

server.port=8080
spring.servlet.multipart.max-file-size=10MB
spring.servlet.multipart.max-request-size=10MB

• Change server.port to run on a different port.
• Adjust multipart limits for larger or smaller uploads.

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Project Structure

src/main/java/com/emmalewis/explore_data_app/
├── ExploreDataAppApplication.java     # Spring Boot entry point
├── controller/
│   └── DataController.java            # Handles upload & visualization endpoints
├── service/
│   └── DataAnalysisService.java       # CSV parsing, stats computation, script generation
└── resources/
    ├── templates/
    │   ├── index.html                 # File upload page
    │   ├── result.html                # Summary report page
    │   └── visualization.html         # Plot display page
    └── application.properties

pom.xml                                # Maven build file
mvnw, mvnw.cmd                         # Maven wrapper scripts