Category Archives: Tips & Tricks

How to Vectorize a Function in R

Last year I came across the base R function Vectorize(). Vectorize() vectorizes the action of a non-vectorized function. Let's give an example. In one of my current research projects, I need to hash patient ids to fulfill the requirements of … Continue reading

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R Markdown Inline Code: Adding a Conjunction to Listings

In my last blog post, I wrote a couple of lines about EFFECT, a clinical trial I'm currently involved in. EFFECT is a cross-over trial with two wash-out and two study phases. After each of the four phases, the participating … Continue reading

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How to Check if a Date is Within a List of Intervals in R

Intro I'm currently involved in a research project called EFFECT. EFFECT is a multicentre, cluster-randomised, placebo-controlled cross-over trial evaluating antiseptic body wash of patients on intensive care units (ICU). The trial is to test whether daily antiseptic body wash reduces … Continue reading

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Drawing a Fish Curve using R and ggplot2

Intro Recently, I wondered whether there is a way to draw a fish shape using a mathematical function. Since I did not find a ready-made R function, I tried to write the function by myself. The equations, I've used for … Continue reading

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How to order factors by level frequency and level name

Intro Quite frequently, factor variables are ordered by level frequency. However, factor levels having only a few observations are sometimes collapsed into one level usually named “others”. Since this level is usually not of particular interest, it may be a … Continue reading

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Postleitzahlen mit führender Null richtig formatieren

Intro Importiert man Postleitzahlen aus anderen Datenformaten (z.B. Excel, Access) in R, ist es nicht selten, dass Postleitzahlen programmintern tatsächlich auch als Zahlen abgespeichert werden. Wie ein Blick auf einen im Internet frei verfügbaren Datensatz zeigt, kann dies zu folgendem … Continue reading

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R Markdown: How to place two tables side by side using ‘knitr’ and ‘kableExtra’

Intro When I was recently writing some report using R Markdown, I wanted to place two rather small tables side by side. Since I usually use the kable()-function of the knitr package and the kableExtra package to print tables, I … Continue reading

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