[R] density(x)
Gavin Simpson
gavin.simpson at ucl.ac.uk
Mon Jul 5 16:57:31 CEST 2004
Christoph Hanck wrote:
> Hello and thanks for your reply
>
> Hopefully, my answer arrives at the correct place like that (if not,
> I am sorry for bothering you, but please let me know...)
>
> To sum up my procedure (sp is exactly the same thing as spr, I had
> just tinkered with the names while trying sth. to solve this problem)
>
>> sp<-read.table("c:/ratsdata/sp3.txt", col.names="sp")
>> xd<-density(sp)
>
> Error in density(sp) : argument must be numeric
>
> The suggested remedies yield the following
>
>> str(sp)
>
> `data.frame': 195 obs. of 1 variable: $ sp: int 11 10 10 12 25 22
> 12 23 13 15 ...
>
>> xd<-density(as.numeric(sp))
>
> Error in as.double.default(sp) : (list) object cannot be coerced to
> double
It is telling you that it cannot convert a list into a numeric object. A
data frame is a list so it is telling you that you cannot convert the
data frame into a numeric vector.
> Hence, it does not seem to be a factor. Declaring it as numeric gives
> another error message, on which I haven't yet found any help in
> Google/the archive.
You want the sp column of the data frame sp not the data frame sp itself
(perhaps you should choose a name for the data frame that is different
to a column name)
> sp <- data.frame(sp = rnorm(100))
> density(sp)
Error in density(sp) : argument must be numeric
> density(sp$sp)
Call:
density(x = sp$sp)
Data: sp$sp (100 obs.); Bandwidth 'bw' = 0.3007
x y
Min. :-3.37457 Min. :0.0001983
1st Qu.:-1.73138 1st Qu.:0.0389884
Median :-0.08819 Median :0.1157180
Mean :-0.08819 Mean :0.1519886
3rd Qu.: 1.55500 3rd Qu.:0.2227940
Max. : 3.19818 Max. :0.4766640
Does this help?
with(sp, density(sp)) would also do what you want, see ?with, and there
are other ways.
Gavin
--
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Gavin Simpson [T] +44 (0)20 7679 5522
ENSIS Research Fellow [F] +44 (0)20 7679 7565
ENSIS Ltd. & ECRC [E] gavin.simpson at ucl.ac.uk
UCL Department of Geography [W] http://www.ucl.ac.uk/~ucfagls/cv/
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