>>>>> Serguei Sokol writes: > Hi, > I came across a case where I cannot access a list element by its empty name. > Minimal example can be constructed as
> x=list("A", 1) > names(x)=c("a", "") > x[["a"]] > #[1] "A" > x[[""]] > #NULL > x$`a` > #[1] "A" > x$`` > # Error: attempt to use zero-length variable name > # but we can still access the second element by its index > x[[2]] > #[1] 1 > To my mind, it should be perfectly legal to access an element by an > empty name as we can have for example > match("", names(x)) > #[1] 2 > Hence a traditional question: is it a bug or feature? A feature according to the docs: ? Extract says Neither empty (‘""’) nor ‘NA’ indices match any names, not even empty nor missing names. -k > Best, > Serguei. >> sessionInfo() > R version 3.5.0 (2018-04-23) > Platform: x86_64-pc-linux-gnu (64-bit) > Running under: Mageia 6 > Matrix products: default > BLAS/LAPACK: /home/opt/OpenBLAS/lib/libopenblas_sandybridge-r0.3.0.dev.so > locale: > [1] C > attached base packages: > [1] stats graphics grDevices utils datasets methods base > loaded via a namespace (and not attached): > [1] compiler_3.5.0 > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel