Java Lesson 5: Classes and Objects
Model real things with classes: fields, constructors, methods, private data with public methods, and records for simple data.
Read article →Coding
Start-to-finish programming for people who work with data: Python, SQL, Java, R, JavaScript, Rust and PowerShell.
Java Lesson 4: Methods
Java Lesson 4: Methods
Write static methods with parameters and return types, overloading, and keeping methods small and testable.
Read article →Java Lesson 3: Conditions and Loops
Java Lesson 3: Conditions and Loops
Use if/else, switch expressions, comparison and logical operators, for, enhanced for and while loops in Java.
Read article →Java Lesson 2: Variables and Types
Java Lesson 2: Variables and Types
Java’s static types: int, double, boolean, char and String, declaring variables, var, arithmetic and integer division, casting and printf formatting.
Read article →Java Lesson 1: Install the JDK and Run Hello World
Java Lesson 1: Install the JDK and Run Hello World
Install a JDK (Temurin or Oracle), check java -version, write and run Hello.java from the terminal and in VS Code or IntelliJ IDEA.
Read article →SQL GROUP BY and HAVING: Pivot Tables Written in SQL
SQL GROUP BY and HAVING: Pivot Tables Written in SQL
Summarise data with SQL GROUP BY, filter groups with HAVING, and understand the difference from WHERE — explained for Excel users with pivot-table comparisons.
Read article →Linux Command Line for Windows Users: 20 Commands to Survive a Server
Linux Command Line for Windows Users: 20 Commands to Survive a Server
The 20 Linux terminal commands you need when you first log in to a server — moving around, reading logs, finding files, permissions and…
Read article →Read and Write Excel Files in Java with Apache POI
Read and Write Excel Files in Java with Apache POI
A beginner-friendly guide to reading and writing .xlsx files in Java using Apache POI — with complete, working examples and common pitfalls.
Read article →Regex for Office Users: Find and Replace Like a Pro
Regex for Office Users: Find and Replace Like a Pro
Learn regex step by step with ten practical patterns — emails, phone numbers, PAN, dates, invoice numbers — usable in Notepad++, VBA, Python, SQL…
Read article →R Lesson 6: Project — A Sales Analysis Report
R Lesson 6: Project — A Sales Analysis Report
Combine reading, dplyr and ggplot2 into a repeatable analysis: KPIs, product summary, charts and output files, plus a pointer to R Markdown/Quarto reports.
Read article →R Lesson 3: Reading CSV and Excel
R Lesson 3: Reading CSV and Excel
Load data into R with readr::read_csv and readxl::read_excel, check columns and types, handle dates and missing values, and write results back out.
Read article →R Lesson 2: Vectors and Data Frames
R Lesson 2: Vectors and Data Frames
R’s building blocks: vectors and vectorised maths, data frames as tables, selecting rows and columns, and checking structure with str and summary.
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