[R] / Operator not meaningful for factors
petr.pikal at precheza.cz
Tue May 4 09:38:25 CEST 2010
r-help-bounces at r-project.org napsal dne 04.05.2010 00:50:00:
> I think that you are correct. R has the annoying habit of converting
> character data to factors when you don't want it to while it is
> data. This is because the in the option "stringsAsFactors" is set to
> some weird historical reasons.
It is a matter of opinion. I consider it quite useful feature. If I see by
str(some.data) or summary(data0 that numeric columns are factors I know
something is wrong with input.
and when I want to use ggplot, xyplot or just plot my data with different
colours/sizes/pchs/.... it is quite easy to use as.numeric(my.factor) to
get numeric representation of levels.
Finally you can easily change labels, concatenate levels and so on.
Just my 2 cents.
> Try the command str(insert name of data) and see what happens. It
> you which columns of data are being treated as factors.
> You can convert the back to character or to numeric. See the FAQ Part 7
> do I convert factors to numeric? " or you can use the String as options
> command in the read.table to FALSE
> Something like this should work, I think, but it's not tested
> read.table("C:/rdata/trees.csv", stringsAsFactors=FALSE)
> --- On Mon, 5/3/10, vincent.deluard <vincent.deluard at trimtabs.com>
> > From: vincent.deluard <vincent.deluard at trimtabs.com>
> > Subject: Re: [R] / Operator not meaningful for factors
> > To: r-help at r-project.org
> > Received: Monday, May 3, 2010, 6:22 PM
> > Hi there,
> > This will sound very stupid because I just started using R
> > but I see you had
> > similar problems.
> > I just loaded a very large dataset (2950*6602) from csv
> > into R. The format
> > is ticker=row, date=column.
> > Every time I want to compute basic operations, R returns
> > "In Ops.factor: not
> > meaningful for factors"
> > I believe it is because R does not read the data as numbers
> > but I am not
> > sure. Can anybody help?
> > Thanks!
> > --
> > View this message in context:
> > Sent from the R help mailing list archive at Nabble.com.
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