[R] Grouping by interval

[Andrej Blejec]

Try this:

Length <- 10:30 
VarA <- seq(1000,1200,10) 
VarB <- seq(500,700,10) 
Data <- cbind(Length,VarA,VarB)
# create a factor of desired Length classes and aggregate
classLength=cut(Length,c(10,15,20,25,30),include.lowest=TRUE) 
aggregate(cbind(VarA,VarB),by=list(LengthClass=classLength),FUN=mean)


LengthClass VarA VarB
1 [10,15] 1025 525
2 (15,20] 1080 580
3 (20,25] 1130 630
4 (25,30] 1180 680

--
Andrej Blejec
National Institute of Biology
Vecna pot 111 POB 141
SI-1000 Ljubljana
SLOVENIA

e-mail: andrej.blejec at nib.si
URL: http://ablejec.nib.si 
tel: + 386 1 423 33 88
fax: + 386 1 241 29 80
--------------------------
Organizer of
Applied Statistics 2008 conference
http://ablejec.nib.si/AS2008 

 


> -----Original Message-----
> From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org]
> On Behalf Of Sonia Mehault
> Sent: Friday, December 07, 2007 10:05 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Grouping by interval
> 
> Hello,
> 
> I have a dataframe of say 20 lines with one line per individual. I
want to
> group these 20 individuals
> by length class (eg. of 5cm) and get the mean value of all the other
> variables (eg VarA and VarB) for each length class
> 
> My dataframe is as follow:
> 
> Length <- 10:30
> VarA <- seq(1000,1200,10)
> VarB <- seq(500,700,10)
> Data <- cbind(Length,VarA,VarB)
> 
> 
> And I want to get something like:
> 
> 
> Length Class      Mean VarA       Mean VarB
> [10-15[               1020                520
> [15-20[               1070                570
> [20-25[               1120                620
> [25-30]               1175                675
> 
> 
> Would you have any suggestions how to do that ?
> Many thanks.
> 
> 
> Sonia.
> 
> 	[[alternative HTML version deleted]]
> 
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