Hi, I just realized that a named empty list is displayed the same way as an empty list: > list(aa=2:5)[0] list() > list() list() For empty atomic vectors, the print method makes the difference: > c(aa=3L)[0] named integer(0) > integer(0) integer(0) Maybe lists could do that too? Thanks, H. > sessionInfo() R version 2.12.0 Under development (unstable) (2010-04-20 r51787) x86_64-unknown-linux-gnu locale: [1] LC_CTYPE=en_CA.UTF-8 LC_NUMERIC=C [3] LC_TIME=en_CA.UTF-8 LC_COLLATE=en_CA.UTF-8 [5] LC_MONETARY=C LC_MESSAGES=en_CA.UTF-8 [7] LC_PAPER=en_CA.UTF-8 LC_NAME=C [9] LC_ADDRESS=C LC_TELEPHONE=C [11] LC_MEASUREMENT=en_CA.UTF-8 LC_IDENTIFICATION=C attached base packages: [1] stats graphics grDevices utils datasets methods base -- Herv? Pag?s Program in Computational Biology Division of Public Health Sciences Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N, M2-B876 P.O. Box 19024 Seattle, WA 98109-1024 E-mail: hpages at fhcrc.org Phone: (206) 667-5791 Fax: (206) 667-1319
>>>>> "HP" == Herv? Pag?s <hpages at fhcrc.org> >>>>> on Thu, 03 Jun 2010 13:25:10 -0700 writes:HP> Hi, HP> I just realized that a named empty list is displayed the same HP> way as an empty list: >> list(aa=2:5)[0] HP> list() >> list() HP> list() HP> For empty atomic vectors, the print method makes the difference: >> c(aa=3L)[0] HP> named integer(0) >> integer(0) HP> integer(0) HP> Maybe lists could do that too? Yes, I agree. I have had at least one situation in the past where I had even been confused for a few minutes by this. I'm about to add it for R-devel [2.12.0] (only; considering it a new feature). Martin Maechler, ETH Zurich
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