[R] adding logical vector to data frame
Prof Brian D Ripley
ripley at stats.ox.ac.uk
Fri Sep 7 21:57:06 CEST 2001
R version?
This works correctly in R-devel. Yes, using $ on data frame subverts some
of the conversions, but logical variables are full-status variables now.
On 7 Sep 2001, Thomas Vogels wrote:
>
> Hello. I'm afraid that I'm missing something very obvious this
> afternoon...
>
> When I add a column to a data.frame (by assigning to a "new" column
> name a logical vector), I thought that I had (at least) 3 options to
> do so:
>
> R> j <- data.frame (x=1:2)
>
> R> j$y <- c(TRUE,FALSE) #assignment 1
> R> str(j)
> `data.frame': 2 obs. of 2 variables:
> $ x: int 1 2
> $ y: logi TRUE FALSE
>
> R> j[["y"]] <- c(TRUE,FALSE) #assignment 2
> R> str(j)
> `data.frame': 2 obs. of 2 variables:
> $ x: int 1 2
> $ y: Factor w/ 2 levels "FALSE","TRUE": 2 1
>
> R> j[["y"]] <- I(c(TRUE,FALSE)) #assignment 3
> R> str(j)
> `data.frame': 2 obs. of 2 variables:
> $ x: int 1 2
> $ y:Class 'AsIs' logi [1:2] TRUE FALSE
>
>
> Why is assignment 1 not identical to either assignment 2 or 3? Is
> there a method dispatch skipped?
>
> Thanks!
> -tom
>
>
> --
> mailto:tov at ece.cmu.edu (Tom Vogels) Tel: (412) 268-6638 FAX: -3204
>
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--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272860 (secr)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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