Thanks to all for the good suggestions!!!
Erin Hodgess, PhD
mailto: erinm.hodg...@gmail.com
On Thu, Sep 20, 2018 at 7:38 PM Rolf Turner <r.tur...@auckland.ac.nz> wrote:
>
> Please see inline below.
>
> n 09/21/2018 01:07 PM, Peter Langfelder wrote:
> > I don't know tibble, so I'll do the same with a plain data frame:
> >
> > a =
> >
> data.frame(x=LETTERS[1:4],y=1:4,z=rnorm(4),a=c("dog","cat","tree","ferret"))
> >> a
> > x y z a
> > 1 A 1 -0.08264865 dog
> > 2 B 2 0.32344426 cat
> > 3 C 3 -0.80416061 tree
> > 4 D 4 1.27052529 ferret
> >> mean(a[2:3])
> > [1] NA
> > Warning message:
> > In mean.default(a[2:3]) : argument is not numeric or logical: returning
> NA
> >> mean(as.matrix(a[2:3]))
> > [1] 1.338395
> >
> > The reason you get an error on mean(a[2:3]) is that a[2:3] is still a
> data
> > frame (a special list) and you cannot simply apply mean to a list. You
> need
> > to first convert to a matrix or vector which can then be fed to mean().
>
> Perhaps
>
> sapply(a[2:3],mean)?
>
> cheers,
>
> Rolf
>
> >
> > Peter
> >
> >
> > On Thu, Sep 20, 2018 at 5:50 PM Erin Hodgess <erinm.hodg...@gmail.com>
> > wrote:
> >
> >> Hello!
> >>
> >> Here is a toy tibble problem:
> >>
> >> xt <-
> >> tibble(x=LETTERS[1:4],y=1:4,z=rnorm(4),a=c("dog","cat","tree","ferret"))
> >> str(xt)
> >> Classes ‘tbl_df’, ‘tbl’ and 'data.frame': 4 obs. of 4 variables:
> >> $ x: chr "A" "B" "C" "D"
> >> $ y: int 1 2 3 4
> >> $ z: num 0.3246 0.0504 0.339 0.4872
> >> $ a: chr "dog" "cat" "tree" "ferret"
> >> #No surprise
> >> xt %>% mean
> >> [1] NA
> >> Warning message:
> >> In mean.default(.) : argument is not numeric or logical: returning NA
> >> #surprised!
> >> mean(xt[2:3])
> >> [1] NA
> >> Warning message:
> >> In mean.default(xt[2:3]) : argument is not numeric or logical:
> returning NA
> >> xt[, 2:3] %>% mean
> >> [1] NA
> >> Warning message:
> >> In mean.default(.) : argument is not numeric or logical: returning NA
> >>
> >> I have a feeling that I'm doing something silly wrong. Has anyone run
> into
> >> this, please? I saw something like this on this list, but didn't see a
> >> solution.
> >>
> >> Thanks,
> >> Erin
>
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