> It seems that the following should work:
This is a common misapprehension. Actually it should not work
for a simple, clear but very commonly misunderstood reason.
>
> > x <- read.table('1A.tab',header=T,skip=1);
> > mode(x[1])
> [1] "list"
> > x[1]
> p01
> R1-00 0.0295
> R1-01 0.0283
> R1-02 0.0145
> R1-03 0.0235
> R1-04 0.0339
> R1-05 0.0239
> R1-06 0.0414
> R1-07 0.0259
> > hist(x[1])
> Error: hist: x must be numeric
> > as.numeric(x[1])
> Error: (list) object cannot be coerced to vector type 14
The problem is that x[1] is not the first component, it is a
sub-list consisting of the first component alone. If you want
the first *component* you have a couple of choices here,
including
x[[1]], x[["p01"]], x[, 1], x$p01 or x[, "p01"]
but not x[1].
> I've worked around the problem by removing the is.numeric()
> test from src/library/base/R/hist.R and in happily produces a
> histogram for me.
In my view modifying standard system functions is always very bad
idea, but I suppose you're the boss on your machine....
> Is there a better way of letting R know that it is working with
> a list of numerics only?
unlist() is designed to flatten lists into vector objects.
--
_________________________________________________________________
Bill Venables, Department of Statistics, Tel.: +61 8 8303 3026
The University of Adelaide, Fax.: +61 8 8303 3696
South AUSTRALIA. 5005. Email: Bill.Venables at adelaide.edu.au
*PLEASE NOTE* From 1 May 1999 my contact details will change to:
-----------------------------------------------------------------
Bill Venables, Statistician, CMIS Environmetrics Project.
Physical address: Postal address:
CSIRO Marine Laboratories, PO Box 120,
233 Middle St, Cleveland, Queensland Cleveland, Qld, 4163
AUSTRALIA AUSTRALIA
Telephone: +61 7 3826 7200 Email: Bill.Venables at cmis.csiro.au
Fax: +61 7 3826 7304
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