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Category: R

Solving Systems of Equations in R

Published 2023-08-16 by Kevin Feasel

Steven Sanderson needs a solution:

In mathematical modeling and data analysis, it is often necessary to solve systems of equations to find the values of unknown variables. R provides the solve() function, which is a powerful tool for solving systems of linear equations. In this blog post, we will explore the purpose of solving systems of equations, explain the syntax of the solve() function, and provide three examples of increasing complexity to demonstrate its usage.

This post got me thinking about linear programming, which is a different topic but still pretty easy to do in R.

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Goldbach’s Conjecture and the Sieve of Sundaram in R

Published 2023-08-14 by Kevin Feasel

Tomaz Kastrun promised us there would be no math on the quiz and yet here we are:

This is fun It is also O(MAX) complexity. But first some background. Since the problem is super old, we are not intending to solve it, merely to play with it. In the number theory of mathematics, the Goldbach’s conjecture states that for every even integer (greater than 2) can be expressed with the sum of two prime numbers. There are also far cries from this theory. For example, prove that every even number can be written as the sum of not more than 300.000 primes (by Schnirelman (1939)).

Read on for the functions and trials of Goldbach’s conjecture.

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Counting Groups in R

Published 2023-08-14 by Kevin Feasel

Steven Sanderson counts items in a group:

As data-driven decision-making becomes more critical in various fields, the ability to extract valuable insights from datasets has never been more important. One common task is to calculate counts by group, which can shed light on trends and patterns within your data. In this guide, we’ll explore three different approaches to achieve this using the powerful R programming language. So, let’s dive into the world of grouped counting with the help of the classic mtcars dataset!

Read on for the base R solution, the dplyr solution (which looks a lot like how we’d solve it in SQL), and the data.table solution.

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Managing Plot Parameters in R

Published 2023-08-10 by Kevin Feasel

Steven Sanderson switches up a visual:

When it comes to data visualization in R, the par() function is an indispensable tool that often goes overlooked. This function allows you to control various graphical parameters, unleashing a world of customization possibilities for your plots. In this blog post, we’ll demystify the par() function, break down its syntax, and provide you with hands-on examples to help you create stunning visualizations.

Click through to check it out. My loyalties definitely lie with ggplot2 for static visual development in R but it’s definitely not the only way to get images to look the way you want them.

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Adding Text to a Plot in R

Published 2023-08-09 by Kevin Feasel

Steven Sanderson texts up a plot:

As a programmer, you’re well aware of the importance of data visualization. A well-crafted plot can convey complex information with clarity and impact. In R, creating stunning plots is a breeze, especially when you’re armed with the versatile text() function. This little gem allows you to add custom text to your plots, enabling you to annotate and highlight essential details. Let’s dive into the world of text() and uncover its syntax and potential through some hands-on examples.

I’m also a big fan of geom_text_repel() in ggplot2’s ggrepel library. It is by no means perfect but it does do a good job of not overlapping important visual features like plotted lines.

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Learning about Data in R with str()

Published 2023-08-07 by Kevin Feasel

Steven Sanderson explains the value of the str() function:

In a nutshell, str() stands for “structure” and offers a concise summary of the structure of an R object. It presents essential details about the object, including its data type, dimensions, and the first few values. By providing an overview of your data, str() allows you to grasp the fundamentals at a glance and proceed with a clearer understanding of what you’re working with.

str() is a really useful function and people who develop objects in R thoughtfully can pack a lot of useful data into the one call.

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Simplifying Nested Lists and Vectors in R

Published 2023-08-03 by Kevin Feasel

Steven Sanderson simplifies things:

Today, we’re diving deep into the incredible world of R programming to explore the often-overlooked but extremely handy unlist() function. If you’ve ever found yourself dealing with complex nested lists or vectors, this little gem can be a lifesaver. The unlist() function is like a magician that simplifies your data structures, making them more manageable and easier to work with. Let’s unlock its magic together!

Click through to see how it works, including explanation and examples.

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ML Model Interactions and hstats

Published 2023-08-02 by Kevin Feasel

Michael Mayer has a new R package for us:

This post is mainly about the third approach. Its beauty is that we get information about all interactions. The downside: it is as good/bad as partial dependence functions. And: the statistics are computationally very expensive to compute (of order n^2).

Different R packages offer some of these H-statistics, including {iml}, {gbm}, {flashlight}, and {vivid}. They all have their limitations. This is why I wrote the new R package {hstats}:

Click through for an overview of the package and an example of how it works.

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