[R] Problem with a non-factor, non-numeric variable in a data.frame

John Kane jrkrideau at yahoo.ca
Tue Nov 6 21:09:16 CET 2007


Have a look at the R-FAQ issue 7.10.   It's a standard
problem

For more information about your variable try

str(variable).


--- Alexandre Santos <alexandre.santos at ochipepe.org>
wrote:

> Dear R list,
> 
> I would like to perform an ANOVA in a set of
> measurements, but I have
> problems formatting the data.
> 
> The data is a two dimensional array containing two
> columns:
> - "Stim" : the type of stimulation (string)
> - "Ratio" : a ratio of two numeric values
> 
> Now, because some values are missing in the data
> (defaulting to zero),
> part of this array will be populated with NA ratios.
> Maybe this is
> important later.
> 
> In order to make the ANOVA analysis, I need to turn
> my vector into a data.frame.
> 
> I tried vector.table=as.data.frame(vector)
> 
> But I realized that
> is.numeric(Ratio) gives FALSE
> is.factor(Ratio) gives TRUE
> 
> After reading the documentation, I tried
> 
> vector.table=as.data.frame(vector, stringsAsFactors
> = FALSE)
> 
> This time
> 
> is.numeric(Ratio) gives FALSE
> is.factor(Ratio) gives FALSE
> 
> So I don't even know what is Ratio, but it's not yet
> numeric (is this
> due to the NA values?).
> 
> How can I get R to understand that Ratio is numeric?
> Checking the
> documentation it seems you can do it with I(x), but
> the details are
> not explained. I also tried as.numeric(Ratio), and
> everything was
> turned into zeros.
> 
> Any suggestions?
> 
> Cheers,
> 
> Alexandre Santos
> 
> Neuro-MPI, Martinsread, Germany
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained,
> reproducible code.
>



More information about the R-help mailing list