Message-ID: <48BC03FC.4080803@biostat.ku.dk>
Date: 2008-09-01T15:02:20Z
From: Peter Dalgaard
Subject: ordered factor and table
In-Reply-To: <48BBF66B.8070002@gvdnet.dk>
Troels Ring wrote:
> dear friends - I have an ordered factor, ID, in a data.frame, labs,
> and make a table,
> aa <- with(labs,table(val >150,ID)) - and now the order in the table
> is according to the alphabetic order in ID, and not as I want it. I
> have tried adding
> [order(unique(labs$ID)] but it doesn't help.
> I have R 2.7.1 on WinXP.
Hi Troels,
I suspect that your notion of "ordered factor" differs from the
technical one. Is the issue that you want ID to have the ordering of
levels as the order of appearance in your data? In that case, try
something like
within(labs, ID <- factor(ID, levels=unique(ID)))
As in:
> x <- c("Crosby","Stills","Nash","Nash","Young")
> ID <- factor(x)
> ID
[1] Crosby Stills Nash Nash Young
Levels: Crosby Nash Stills Young
> ID <- factor(ID, levels=unique(ID))
> ID
[1] Crosby Stills Nash Nash Young
Levels: Crosby Stills Nash Young
> table(ID)
ID
Crosby Stills Nash Young
1 1 2 1
--
O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907