Articles by S. Richter-Walsh

Cats are great and so is the forcats R package

March 28, 2018 | S. Richter-Walsh

Cats are great. Perhaps Hadley Wickham and Lionel Henry think so too given the wonderful choice of name for their purrr package. Hadley Wickham has also created a superb package called forcats, likely  an abbreviation of “for categoricals” but wittingly cat-themed, which is very, very useful to the data scientist. ...
[Read more...]

Useful dplyr Functions (w/examples)

July 10, 2017 | S. Richter-Walsh

The R package dplyr is an extremely useful resource for data cleaning, manipulation, visualisation and analysis. It contains a large number of very useful functions and is, without doubt, one of my top 3 R packages today (ggplot2 and reshape2 being the others). When I was learning how to use dplyr ... [Read more...]

Ordinary Least Squares (OLS) Linear Regression in R

July 4, 2017 | S. Richter-Walsh

Ordinary Least Squares (OLS) linear regression is a statistical technique used for the analysis and modelling of linear relationships between a response variable and one or more predictor variables. If the relationship between two variables appears to be linear, then a straight line can be fit to the data in ...
[Read more...]

Bland-Altman/Tukey Mean-Difference Plots using ggplot2

May 31, 2017 | S. Richter-Walsh

A very useful data visualisation tool in science, particularly in medical and sports settings, is the Bland-Altman/Tukey Mean-Difference plot. When comparing two sets of measurements for the same variable made by different instruments, it is often required to determine whether the instruments are in agreement or not. Correlation and ...
[Read more...]

ggplot2 style plotting in Python

May 8, 2017 | S. Richter-Walsh

R is my language of choice for data science but a good data scientist should have some knowledge of all of the great tools available to them. Recently, I have been gleefully using Python for machine learning problems (specifically pandas and the wonderful scikit-learn). However, for all its greatness, I ...
[Read more...]

Naive Bayes Classification in R (Part 2)

February 17, 2017 | S. Richter-Walsh

Following on from Part 1 of this two-part post, I would now like to explain how the Naive Bayes classifier works before applying it to a classification problem involving breast cancer data. The dataset is sourced from Matjaz Zwitter and Milan Soklic from the Institute of Oncology, University Medical Center in ... [Read more...]

Naive Bayes Classification in R (Part 1)

February 17, 2017 | S. Richter-Walsh

Introduction A very useful machine learning method which, for its simplicity, is incredibly successful in many real world applications is the Naive Bayes classifier. I am currently taking a machine learning module as part of my data science college course and this week’s practical work involved a classification problem ... [Read more...]

Implementing the Gradient Descent Algorithm in R

February 12, 2017 | S. Richter-Walsh

A Brief Introduction Linear regression is a classic supervised statistical technique for predictive modelling which is based on the linear hypothesis: y = mx + c where y is the response or outcome variable, m is the gradient of the linear trend-line, x is the predictor variable and c is the intercept. ...
[Read more...]

IMDB Movie Analysis

January 19, 2017 | S. Richter-Walsh

Movies of late haven’t impressed (this viewer anyhow) and I keep finding myself returning to classics of the 1980’s and 1990’s to get my movie fix. While browsing through Kaggle datasets, I came across the IMDB 5000 Movie Dataset which contains data on over 5000 movies scraped from the IMDB website. ...
[Read more...]

The other carbon dioxide problem.

August 2, 2015 | S. Richter-Walsh

Researchers say ocean acidification may have dramatic effects on phytoplankton. Edit section Phytoplankton, tiny plants which live in the ocean, form the foundation of the marine food web and play an important role in the regulation of Earth’s climate. These wonderful organisms create their own food using sunlight, nutrients ...
[Read more...]


July 31, 2013 | S. Richter-Walsh

We know much as a species yet we have so much more to learn. Each of us alive today could just as easily have been born into consciousness centuries or millenia ago, and have had little idea that the Earth revolved around the Sun nor that our solar system was ...
[Read more...]

Our Acid Earth

July 27, 2013 | S. Richter-Walsh

The Earth’s oceans, soils, and freshwater bodies are acidifying. Acid rain was in the media a lot in the 80’s and 90’s but has been forgotten as of late. This ignored menace is having many negative effects on the environment. Fossil fuel combustion, transportation emissions, deforestation, and the mining ...
[Read more...]

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)