Data Science Educational Resources
StrataScratch is a data science educational platform with over 1,000+ real interview questions from your favorite companies.
Interviews
Using Principal Component Analysis in R for Real-World Data
A hands-on guide to using PCA in R with DoorDash data—cleaning, visualising, and modelling compressed dimensions that actually make sense.
Nathan Rosidi -
Looping Through Lists in Python: A Comprehensive Tutorial
Learn how to loop through a list in Python using real Uber data, practical techniques, and performance-friendly tips.Nathan Rosidi -
A Comprehensive Step-by-Step Guide to Full Outer Join in SQL
The FULL OUTER JOIN is a very useful but often overlooked SQL join. In this article, we’ll discuss how it works, when to use it, and give practical examples.Nathan Rosidi -
How to Create a Matplotlib Histogram?
A Matplotlib histogram is a common data visualization in data science. Here, you will learn all the fundamentals of creating and customizing histograms.Nathan Rosidi -
Introduction to Polars: Everything You Must Know?
Explore how Polars surpasses Pandas in speed and efficiency with a step-by-step breakdown of a real Visa interview question on calculating customer densityNathan Rosidi -
How to Customize Matplotlib Colors for Better Plots?
Customizing Matplotlib colors is more than just choosing your favorite color for a plot. Colors play a crucial role in communicating your data’s message.Nathan Rosidi -
Getting Started with PlotlyJS: A Beginner's Guide
Learn how to create interactive charts with PlotlyJS in JavaScript—no setup needed, just code directly in your browser.Nathan Rosidi -
ML Interviews are Ridiculous And All Over the Place
If you think ML interviews have become crazy lately, you’re not imagining it. They are ridiculous, and we’ll examine why in this ranty article.Nathan Rosidi -
Data Structures and Algorithms in Python for Beginners
The article will teach you the basics of data structures and algorithms in Python. Arrays, lists, dictionaries, tuples, sets, and queues are all there and more.Nathan Rosidi -
How to Find the Minimum Value in SQL (with Examples)
Finding the minimum in SQL is easy: just use the MIN() aggregate function. In this article, you will learn how to do it in different real-case scenarios.Nathan Rosidi -
Easy Guide to Python Hashmaps
What are Python hashmaps, what are the basic operations and advanced techniques, and how to use them in practice? We answer all that and more in this article.Nathan Rosidi -
Mastering Row Number Handling in SQL Queries
ROW_NUMBER() is one of the essential ranking window functions in SQL. Learn where you can use it and how it works with ORDER BY and PARTITION BY window clauses.Nathan Rosidi -