[R] Dataframe manipulation

[Dimitris Rizopoulos]

try this (also look at R-FAQ 7.10):

sapply(df, function (x) as.numeric(levels(x))[as.integer(x)])


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Antje" <niederlein-rstat at yahoo.de>
To: <r-help at stat.math.ethz.ch>
Sent: Tuesday, December 04, 2007 11:46 AM
Subject: [R] Dataframe manipulation


> Hello,
>
> can anybody help me with this problem?
> I have a dataframe, which contains its values as factors though I 
> have numbers
> but it was read as factors with "scan". Now I would like to convert 
> these
> columns (multiple) to a numeric format.
>
>
> # this example creates a similar situation
>
> testdata <- as.factor(c("1.1",NA,"2.3","5.5"))
> testdata2 <- as.factor(c("1.7","4.3","8.5",10.0))
>
> df <- data.frame(testdata, testdata2)
>
> what do I have to do to get the same datafram but with numeric 
> values???
>
> Antje
>
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