[R] Bug in "==" with empty data frames

[Rainer M Krug]

Hi

The following code results in an error:


###########
> x <- data.frame(x = integer(0), y = integer(0))
> x == x
Error in matrix(if (is.null(value)) logical() else value, nrow = nr, dimnames = list(rn,  :
  length of 'dimnames' [2] not equal to array extent
>
###########

I would expect that it returns logical(0) as both have the same structure and both are empty, or even TRUE?

But definitely not an error.

Cheers,

Rainer

###########
> sessionInfo()
R version 3.6.1 (2019-07-05)
Platform: x86_64-apple-darwin17.7.0 (64-bit)
Running under: macOS High Sierra 10.13.6

Matrix products: default
BLAS:   /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libLAPACK.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

loaded via a namespace (and not attached):
[1] compiler_3.6.1
###########

--
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology, UCT), Dipl. Phys. (Germany)

Orcid ID: 0000-0002-7490-0066

Department of Evolutionary Biology and Environmental Studies
University of Zürich
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