• Created a tool that estimates price of a used car(MAE ~ $4K) to help the buyer negotiate while shopping and individuals who want to list their car on platforms like Facebook Marketplace.
• Scraped over 2000 car listings in California and NewYork from cargurus.com (listing website of used car) using selenium.
• Cleaned data and engineered features (such as model, built year, mileage, details, and description) from raw data.
• Performed EDA (exploratory data analysis) to handle missing values, remove outliers, transform variables, check correlation and shortlist variables for machine learning model building.
• Optimized Linear, Lasso, Ridge, Random Forest, and XGBoost regressors using GridsearchCV to find the best model.
• Deployed in Heroku cloud using Flask API endpoint. Made it available online for users to get an approximate price of the car. Link given in Productionization section below.

• Python Version: 3.8.5
• Packages: pandas, numpy, sklearn, xgboost, matplotlib, seaborn, selenium, nltk
• For Web Framework Requirements: pip install -r requirements.txt
• GitHub Repo Ref: https://github.com/PlayingNumbers/ds_salary_proj
• Deployment Ref: https://medium.com/@nutanbhogendrasharma/deploy-machine-learning-model-with-flask-on-heroku-cd079b692b1d

Scraped over 2000 car listing from cargurus.com using selenium. The following information were extracted from each listing:

• Price of car
• Build year
• Model of the car (Ford, Toyota, Honda, etc.)
• Gas Mileage
• Features (Bluetooth, Alloy wheels, Android Auto, Backup Camera, Heated seats, etc.)
• Transmission (Automatic and Manual)
• Color
• Engine
• Drivetrain
• Fuel type
• Description

Cleaned the raw data and made new columns with proper assignment of variables.

• Parsed numeric and categorical variables out of text.
• Made columns for price, model, and build year of the car.
• Parsed details such as Transmission, Color, Engine, Drivetrain, Fuel_type, Gas mileage into separate columns from a single column.
• Column for description length
• Counted number of features such as Bluetooth, keyless entry, type of wheel, heated seats, etc, and saved into one column.

Plotted distribution of continous and categorial variables. Imputed missing values and removed outliers. Highlights from EDA notebook are as follows:

• Transformed the categorical variables into binary format using One-Hot encoding.
• Split the dataset into 80:20 for train and test respectively.
• Used MAE (Mean Absolute Error) to evaluate model. MAE is good with outliers.
• Used five models:
  • Multilinear regression - Baseline for the model.
  • Ridge regression - To prevent overfitting.
  • Lasso regression - Effective because data is sparse for many categorical variables.
  • Random Forest - Could be a good fit for sparse data type.
  • XGBoost - Most advanced algorithm for sparse data. Also, hypertuned the parameters using GridsearchCV.

XGBoost performed the best:

• Multilinear regression: MAE = $4968
• Ridge regression: MAE = $4968
• Lasso regression: MAE = $4914
• Random Forest: MAE = $4596
• XGBoost: MAE = $4185

Built a Flask API endpoint and hosted on webserver using heroku. The following page takes user inputs and estimate the price of car. Refer this link to checkout deployment page: https://carpricechecker.herokuapp.com/

• Average price of used cars listed in cargurus.com is ~$20K in California and NewYork.
• Major factors that affect the price of used cars is in following order: mileage > built year > gas mileage > features > color > engine > drivetrain
• Pipeline can be implemented for data cleaning, EDA and model building to streamline the process.
• Accuracy of model can be improved by selecting better features, variable transformation(skewed to normal distribution), and removal of more outliers.
• NLP can be used to get insight from descriptions.

Use the link below and copy paste the git repository link into it for a smooth experience. https://nbviewer.jupyter.org/