R Cook Book

tropf

ABSTRACT

My personal recipes when using R.

1. Intro

I use R mainly for plotting and some data post-processing. This document collects some tricks I encountered and use.

For plotting I use ggplot2, which ist assumed to exist in these examples. A variable p is typically a ggplot2 plot object.

2. Hiding Legend, but Preserving its Space

To hide a legend, but still take up its space (e.g. to build plots over multiple instances) add the following to the legend. Adjust the aesthetic used.

p <- p +
    guides(fill=guide_legend(override.aes=list(fill=NA))) +
    theme(legend.text=element_text(color="#00000000"),
          legend.title=element_text(color="#00000000"))

3. aggregate() with more than one output value

To aggregate with multiple outputs, use the following snippet. Note that this only works if all outputs have the same type.

aggrs <- aggregate(to_be_summarized ~ category,
                   df,
                   function(v){c(mean=mean(v), sd=sd(v), min=min(v), max=max(v))})
extra_df <- data.frame(aggrs$to_be_summarized)
aggrs$to_be_summarized <- NULL
colnames(extra_df) <- paste("to_be_summarized", colnames(extra_df), sep=".")
aggrs <- cbind(aggrs, extra_df)
rm(extra_df)

02 October 2024
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