Data Science Educational Resources
StrataScratch is a data science educational platform with over 1,000+ real interview questions from your favorite companies.
Interviews
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 -
Finding Maximum Values in SQL: Aggregation Techniques
MAX() in SQL is a straightforward aggregation method for finding maximum values. Learn here about its syntax and use cases through real interview examples.Nathan Rosidi -
CONCAT() in SQL: Tips and Techniques for Efficient Queries
CONCAT() in SQL is a data concatenation method. Learn about the tips, techniques, and practical examples of how to use it efficiently in SQL queries.Nathan Rosidi -
How to Replace a Character in a Python String
There are several ways to replace a character in a Python string. In this article, you’ll learn three main techniques and how to use them in practice.Nathan Rosidi -
Mastering Loop Iterations: Python For Loop Index Explained
Use Python's for loop index to manage data efficiently, improve performance, and ensure smoother processing, especially with large datasets or complex tasks.Nathan Rosidi -
PySpark SQL Functions: Boost Big Data Processing with SQL
Leverage PySpark SQL Functions to efficiently process large datasets and accelerate your data analysis with scalable, SQL-powered solutions.Nathan Rosidi -
Counting Distinct Values in SQL: Tips and Examples
Using SQL COUNT(DISTINCT) is an easy way to count distinct values in SQL. However, it has its own quirks, which we’ll explain (with examples) in this article.Nathan Rosidi -
Commonly Asked Data Structure Interview Questions
Data structure interview questions are a big part of interviews for many data roles. To answer them, you should know the data structures we’ll cover here.Nathan Rosidi -
The Fundamentals of Structuring Data
Mastering data structuring is key to efficiently organizing, accessing and make sense of the vast amounts of data we interact with on a daily basis.Nathan Rosidi -
How Do You Perform SQL LIKE Queries for Pattern Matching?
The LIKE SQL query allows you to perform a pattern-matching search of your text data. Learn how to use it and add wildcards for increased flexibility.Nathan Rosidi -
What is Big O Notation? (+ Cheat Sheet)
Big O Notation helps developers predict how an algorithm's performance scales with input size, guiding them to choose the most efficient solution.Nathan Rosidi -