R6DS v1.2.0


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R6 Reference Class Based Data Structures

Provides reference classes implementing some useful data structures. The package implements these data structures by using the reference class R6. Therefore, the classes of the data structures are also reference classes which means that their instances are passed by reference. The implemented data structures include stack, queue, double-ended queue, doubly linked list, set, dictionary and binary search tree. See for example <https://en.wikipedia.org/wiki/Data_structure> for more information about the data structures.


R6DS version 1.2.0 (Red DS)

R6DS stands for R6 class based Data Structures. The package provides reference classes implementing some useful data stuctures. They are:

For an introduction of the package, please read the online vignette

Introduction to the R6DS Package

How to install

You can either install the stable version from CRAN


or install the development version from GitHub


provided that the package “devtools” has been installed beforehand.

Get started

After installing the package, you need to load (attach better say) it by running the code


You can first check the information and the current version number by running

#> R6DS version 1.2.0 (Red DS)

Then you can take a look at all the available functions and data in the package

ls( grep("R6DS", search()) ) 
#> [1] "RBST"    "RDeque"  "RDict"   "RDLL"    "RQueue"  "RSet"    "RStack" 
#> [8] "version"

Now you can dive deeply into the package by reading the manual



Something need to be clarified!

It is quite straightforward to create a new instance of the class in the package. What you can do, for example, is to use the new function

rstack <- RStack$new()

and an empty stack (rstack) will be initialized.

You can push elements into it.

rstack$push(1, 2, 3)

and even heterogeneous elements

rstack$push("Hello world!", list(key=1, val=2), RQueue$new())

Notice that, the last pushed element is an instance of the class RQueue in the package.

Remember that, in R, only the assignment or pass of an instance of some reference class is pass-by-reference! In the following sentence, rstack pops the last stacked element (return and remove its handle in rstack) and assign it by-reference to rqueue

rqueue <- rstack$pop()

And the following assignments are pass-by-value (a copy).

rlist <- rstack$pop()
rstring <- rstack$pop()

The difference between the two assignments are:

  • rqueue takes over the same memory space with the used-to-be-the-last (but not ever since the pop) element in rstack, and R did not allocate memory space when creating rqueue.
  • rlistand rstring are variables with newly allocated memory spaces. As for the list and string elements in rstack, they have been removed completely.

So the conclusion is that, whether it is a pass-by-value or by-reference depends on the object to be passed, not anything else.

Functions in R6DS

Name Description
R6DS R6DS: provides reference classes implementing some useful data stuctures.
version Show the version number of some information.
RDict The RDict reference class
RStack The RStack reference class
RDeque The RDeque reference class
RQueue The RQueue reference class
RDLL The RDLL reference class
RSet The RSet reference class
RBST The RBST reference class
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Vignettes of R6DS

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Type Package
License GPL-3
Encoding UTF-8
LazyData true
RoxygenNote 6.1.1
URL https://github.com/yukai-yang/R6DS
BugReports https://github.com/yukai-yang/R6DS/issues
VignetteBuilder knitr
NeedsCompilation no
Packaged 2019-05-21 10:53:14 UTC; yyang
Repository CRAN
Date/Publication 2019-05-21 11:00:03 UTC
suggests knitr , rmarkdown
depends R (>= 3.0.0)
imports R6

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