I import financial data from Yahoo Finance and other sites, and create time series charts using Quantmod - a Quantitative Financial Modelling & Trading Framework for R. I add a layer of technical analysis using TTR package.

I build a natural language index on a document, first "by hand" and then using PostgreSQL inbuilt features.

I create an inverted string index on a document, first "by hand" and then using PostgreSQL inbuilt features.

I import into a SQL database an archive of e-mail correspondence and search through it using regular expressions.

The document gives an overview of regular expressions in PostgreSQL, with examples of queries including single and multiple matches.

The document showcases various text functions, evaluated on a randomly generated dataset, along with an analysis of query performance.

The task is to design a database model representing flat data across multiple linked tables using "third-normal form" (3NF), i.e. columns with vertical duplication must be placed in separate tables and linked into the main table using a foreign key.  

The document is created in Quarto accessed from RStudio connected to a locally hosted PostgreSQL database.

The document is created in Quarto accessed from RStudio connected to a PostgreSQL database.

The document is created in Quarto accessed from RStudio, with a connection to a PostgreSQL database..

I focus on reducing vertical duplication in the result set with DISTINCT, DISTINCT ON and GROUP BY ... HAVING The document is created in Quarto accessed from RStudio.

The document is created in Quarto accessed from RStudio.

I create a database with a "many to many" relationship. The document is created in Quarto accessed from RStudio.

This document is created in Quarto accessed from RStudio.

A quick overview of a data preparation process - from downloading and cleaning to subsetting, filtering, and first visualizations with ggplot2.