[R] more woes trying to convert a data.frame to a numerical matrix

[ONKELINX, Thierry]

?as.numeric

------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Reseach Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium
tel. + 32 54/436 185
Thierry.Onkelinx op inbo.be
www.inbo.be 

Do not put your faith in what statistics say until you have carefully
considered what they do not say.  ~William W. Watt
A statistical analysis, properly conducted, is a delicate dissection of
uncertainties, a surgery of suppositions. ~M.J.Moroney

 

> -----Oorspronkelijk bericht-----
> Van: r-help-bounces op stat.math.ethz.ch 
> [mailto:r-help-bounces op stat.math.ethz.ch] Namens Andrew Yee
> Verzonden: woensdag 16 mei 2007 14:11
> Aan: r-help op stat.math.ethz.ch
> Onderwerp: [R] more woes trying to convert a data.frame to a 
> numerical matrix
> 
> I have the following csv file:
> 
> name,x,y,z
> category,delta,gamma,epsilon
> a,1,2,3
> b,4,5,6
> c,7,8,9
> 
> I'd like to create a numeric matrix of just the numbers in 
> this csv dataset.
> 
> I've tried the following program:
> 
> sample.data <- read.csv("sample.csv")
> numerical.data <- as.matrix(sample.data[-1,-1])
> 
> However, print(numerical.data) returns what appears to be a matrix of
> characters:
> 
>   x   y   z
> 2 "1" "2" "3"
> 3 "4" "5" "6"
> 4 "7" "8" "9"
> 
> How do I force it to be numbers rather than characters?
> 
> Thanks,
> Andrew
> 
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> 
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