The problem is that within.data.frame calls as.list.environment with
the default value of all.names = FALSE. I doubt this is a deliberate
feature, and is more likely to be a minor oversight.
Hadley
On Sun, Sep 20, 2015 at 11:49 AM, Brian <zenli...@gmail.com> wrote:
> Dear List,
>
> Somewhere I missed something, and now I'm really missing something!
>
>> d.f <- data.frame(.id = c(TRUE, FALSE, TRUE), dummy = c(1, 2, 3), a =
> c(1, 2, 3), b = c(1, 2, 3) + 1)
> > within(d.f, {d = a + b})
> dummy a b d
> 1 1 1 2 3
> 2 2 2 3 5
> 3 3 3 4 7
> > d.f <- data.frame(.id = c(TRUE, FALSE, TRUE), .dummy = c(1, 2, 3), a
> = c(1, 2, 3), b = c(1, 2, 3) + 1)
> > within(d.f, {d = a + b})
> a b d
> 1 1 2 3
> 2 2 3 5
> 3 3 4 7
>
> Could somebody please explain to me why this does this? I think could be
> considered a feature (for lots of calculations within a data frame you
> don't have to remove all extra variables at the end). I just wish it
> was documented.
>
> Cheers,
> Brian
>
>
> sessionInfo()
> R version 3.1.0 (2014-04-10)
> Platform: x86_64-pc-linux-gnu (64-bit)
>
> locale:
> [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
> [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
> [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
> [7] LC_PAPER=en_US.UTF-8 LC_NAME=C
> [9] LC_ADDRESS=C LC_TELEPHONE=C
> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
>
> attached base packages:
> [1] splines grid stats graphics grDevices utils datasets
> [8] methods base
>
> other attached packages:
> [1] scales_0.2.4 plyr_1.8.3 reshape2_1.4
> ccchDataProc_0.7
> [5] ccchTools_0.6 xtable_1.7-4 tables_0.7.79 Hmisc_3.14-5
> [9] Formula_1.1-2 survival_2.37-7 ggplot2_1.0.1
> IDPmisc_1.1.17
> [13] lattice_0.20-29 myRplots_1.1 myRtools_1.2 meteoconv_0.1
> [17] pixmap_0.4-11 RColorBrewer_1.0-5 maptools_0.8-30 sp_1.1-1
> [21] mapdata_2.2-3 mapproj_1.2-2 maps_2.3-9 chron_2.3-45
> [25] MASS_7.3-35
>
> loaded via a namespace (and not attached):
> [1] acepack_1.3-3.3 cluster_1.15.2 colorspace_1.2-4
> [4] compiler_3.1.0 data.table_1.9.4 digest_0.6.4
> [7] foreign_0.8-61 gtable_0.1.2 labeling_0.3
> [10] latticeExtra_0.6-26 munsell_0.4.2 nnet_7.3-8
> [13] proto_0.3-10 Rcpp_0.12.0 rpart_4.1-8
> [16] stringr_0.6.2 tools_3.1.0
> > within
> function (data, expr, ...)
> UseMethod("within")
> <bytecode: 0x26d32c8>
> <environment: namespace:base>
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
--
http://had.co.nz/
______________________________________________
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