Hi everyone,

Happy New Year, it’s 2024! This month we’re meeting in 50 George Square, G.06 at 5.30pm on Friday 26th Jan. We’ve two talks on rolling statistics, or moving windows.

Register here: https://www.meetup.com/edinbr/events/298492818

• Jan Gorecki came to R around 2013 when databases happened to be not enough for data analytics. Once he discovered data.table he never went back to databases for data processing. Amazed by data.table’s UX (simply a base R data.frame on steroids), he started contributing high level functions that he used in databases and data warehouses. Over years he jumped into C and from 2018 contributed first high performance routines. Used R in production in UK mortgages company and in H2O.ai as infrastructure orchestration. Developed many R packages over years. Taught by the time to be very conservative in (and if !) picking dependencies.

• Nick Christofides is a Healthcare Analyst at Public Health Scotland. With a background in statistics, epidemiology, and finance, he enjoys utilising his technical expertise to analyse healthcare data, building tools to help solve real-world problems. During the COVID-19 pandemic, he played a vital role in reporting key trends and insights to the Scottish government and NHS Boards. In this time he gained a particular interest in time series data, one of the inspirations for timeplyr. Also in his spare time he enjoys cooking, drumming, and writing R code.

Rolling statistics

Jan Gorecki

Slides (pdf): click here

Rolling statistics are an interesting topic for optimizations, therefore in my talk I will use R language to present naive implementation, and the optimized implementation, on a simple case of rolling mean. Then I will move to data.table implementations of rolling statistics explaining possible optimizations in other functions, which are not that straightforward anymore, like min/max and, actually very complex, median. Finally benchmarks will be presented comparing data.table implementations to base R, pandas, polars, slider/dplyr, duckdb and spark.

timeplyr - Fast Tidy Functions for Date and Time Manipulation

Nick Christofides

Slides (web page): click here

We all know dates in R are difficult and frustrating at the best of times, so timeplyr seeks to make this much easier!

While most time-based packages are designed to work with relatively small, clean and aggregate data, timeplyr contains a set of tidy tools to efficiently handle big messy data, as well as being able to naturally manage many time-based variables such as dates, date-times, year-months and others.

timeplyr aims to be a companion to the successful dplyr package but with speed in mind, with most of the calculations combining the speed of collapse and the efficiency of data.table.

January 2024: Rolling statistics and moving windows