[R] Why isn't R recognising integers as numbers?

[Marc Schwartz]

on 09/21/2008 08:01 PM Ted Byers wrote:
> I have a number of files containing anywhere from a few dozen to a few
> thousand integers, one per record.
> 
> The statement "refdata18 =
> read.csv("K:\\MerchantData\\RiskModel\\Capture.Week.18.csv", header =
> TRUE,na.strings="")" works fine, and if I type refdata18, I get the integers
> displayed, one value per record (along with a record number).  However, when
> I try " fitdistr(refdata18,"negative binomial")", or hist.scott(refdata18,
> prob = TRUE), I get an error:
> 
> Error in fitdistr(refdata18, "negative binomial") : 
>   'x' must be a non-empty numeric vector
> Or
> Error in hist.default(x, nclass.scott(x), prob = prob, xlab = xlab, ...) : 
>   'x' must be numeric
> 
> How can it not recognise integers as numbers?
> 
> Thanks
> 
> Ted

'refdata18' is a data frame and the two functions are expecting a
numeric vector.

If you use:

  fitdistr(refdata18[, 1], "negative binomial")

or

  hist(refdata18[, 1])

you should get a suitable result, presuming that the first column in the
data frame is a numeric vector.

Use:

  str(refdata18)

to get a sense for the structure of the data frame, including the column
names, which you could then use, instead of the above index based syntax.

HTH,

Marc Schwartz