Implementation of core data structures for R.

## Introduction

Implementation of advanced data structures such as hashmaps, heaps, or queues in R. Advanced data structures are essential in many computer science and statistics problems, for example graph algorithms or string analysis. The package uses Boost and STL data types and extends these to R with Rcpp modules.

So far datastructures has implementations for:

• Fibonacci and binomial heaps,
• queues and stacks,
• hashmaps, multimaps and bimaps.

As an introductory example, imagine that you want to compute shortest paths on a graph and decide to use a Fibonacci heap for keeping the distances. A Fibonacci heap is an efficient tree-like data structure that satisfies the min-heap property. We can use it to quickly get the node with the shortest distance in O(log n) time like this:

  fh <- fibonacci_heap("numeric")
node.labels    <- paste0("n", 10:1)
node.distances <- seq(1, 0, length.out=length(node.labels))
fh <- insert(fh, node.distances, node.labels)

peek(fh)
\$0
[1] "n1"

datastructures also allows storing non-orimitive objects, like data.frames, matrices or environments. For instance, we could use a hashmap for storing such objects:

  hm <- hashmap("integer")
keys <- 1:2
values <- list(
environment(),
data.frame(A=rbeta(3, .5, .5), B=rgamma(3, 1)))
hm[keys] <- values

hm[1L]
[[1]]
<environment: R_GlobalEnv>

## Installation

Get the package from CRAN using:

  install.packages("datastructures")

You can also download the tarball of the latest release and install with:

  R CMD install <datastructures-x.y.z.tar.gz>

where <datastructures-x.y.z.tar.gz> is your downloaded tarball. If you want to you can also use devtools, but I don’t recommend it since it might give unstable versions:

  devtools::install_github("dirmeier/datastructures")

## Documentation

Load the library using library(datastructures). We provide a vignette for the package that can be called using: vignette("datastructures"). If there are any questions let met know.

## Citation

If you want to cite datastructures, please use the following entry:

Dirmeier, Simon (2018). datastructures: An R package for organisation and storage of data. Journal of Open Source Software, 3(28), 910, https://doi.org/10.21105/joss.00910

## Feature requests and contributing

If you want to have another datastructure added, say from boost or the STL, just open up a new issue. Alternatively it would be great if you provided a PR.