Hi,
thanks for your replies regarding the problem to select a sub data frame by
expression. I start getting an understanding on how indexing works in R.
thanks for your replies,
Arne
> -----Original Message-----
> From: Prof Brian Ripley [mailto:[EMAIL PROTECTED]
> Sent: 17 October 2003 12:38
> To: Muller, Arne PH/FR
> Cc: [EMAIL PROTECTED]
> Subject: Re: [R] sub data frame by expression
>
>
> On Fri, 17 Oct 2003 [EMAIL PROTECTED] wrote:
>
> > I've the following data frame with 54 rows and 4 colums:
> >
> > > x
> > Ratio Dose Time Batch
> > R.010mM.04h.NEW 0.02 010mM 04h NEW
> > R.010mM.04h.NEW.1 0.07 010mM 04h NEW
> > ...
> > R.010mM.24h.NEW.2 0.06 010mM 24h NEW
> > R.010mM.04h.OLD 0.19 010mM 04h OLD
> > ...
> > R.010mM.04h.OLD.1 0.49 010mM 04h OLD
> > R.100mM.24h.OLD 0.40 100mM 24h OLD
> >
> > I'd like to create a sub data frame containing all rows
> where Batch == "OLD"
> > and keeping the 4 colums. Assume that I don't know the
> order of the rows
> > (otherwise I could just do something like x[1:20,]).
> >
> > I've tried x[x$Batch == 'OLD'] or x[x[,4] == 'OLD'] but it
> generates errors.
>
> That subsets columns, not rows. Try x[x$Batch == "OLD",]
>
> --
> Brian D. Ripley, [EMAIL PROTECTED]
> Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
> University of Oxford, Tel: +44 1865 272861 (self)
> 1 South Parks Road, +44 1865 272866 (PA)
> Oxford OX1 3TG, UK Fax: +44 1865 272595
>
>
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