R help - Sep 2007 - aggregate factor

Hi,
I am using aggregate to compute means for later plotting.
There are two factors involved and the problem is that the values of the 
second factor ( Age ) in the means are not in the right order because 
"10" comes inbetween "1" and "2"
What I really want is the numeric value of Age but as.numeric and 
as.integer returns the level value instead.
Is there a way to easily get the numeric value?
I am using Windows R 2.5.1

Thanks,

 > str(fishdata)
'data.frame':   372 obs. of  6 variables:
 $ Lake: Factor w/ 3 levels "EVANS","JOLLIET",..: 3 3 3 3 3
3 3 3 3 3 ...
 $ Age : int  1 1 1 1 1 1 1 1 1 1 ...
 $ TL  : int  132 120 125 115 130 120 115 110 117 116 ...
 $ W   : int  10 10 10 10 10 10 10 10 10 20 ...
 $ Sex : Factor w/ 3 levels "F","I","M": 1 1 2 2 2
1 1 1 2 2 ...
 $ WT  : num  0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23 ...
 > fishdatameans=aggregate(fishdata$TL, list(Lake = fishdata$Lake, 
Age=fishdata$Age), mean)

#  Now Age is a Factor but 10 is in the wrong position.
 > fishdatameans$Age
 [1] 0  1  1  1  2  2  2  3  3  3  4  4  4  5  5  6  6  6  7  8  9  10
Levels: 0 1 10 2 3 4 5 6 7 8 9

 > as.numeric(fishdatameans$Age)
 [1]  1  2  2  2  4  4  4  5  5  5  6  6  6  7  7  8  8  8  9 10 11  3
 >
# What I want  is ---->   0  1  1  1  2  2  2  3  3  3  4  4  4  5  5  
6  6  6  7  8  9  10

Bill

Try this.

as.numeric(levels(fishdata$Age))[fishdata$Age]

HTH,

Thierry

------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research 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 Bill Szkotnicki
> Verzonden: vrijdag 7 september 2007 21:10
> Aan: r-help op stat.math.ethz.ch
> Onderwerp: [R] aggregate factor
> 
> Hi,
> I am using aggregate to compute means for later plotting.
> There are two factors involved and the problem is that the 
> values of the second factor ( Age ) in the means are not in 
> the right order because "10" comes inbetween "1" and
"2"
> What I really want is the numeric value of Age but as.numeric 
> and as.integer returns the level value instead.
> Is there a way to easily get the numeric value?
> I am using Windows R 2.5.1
> 
> Thanks,
> 
>  > str(fishdata)
> 'data.frame':   372 obs. of  6 variables:
>  $ Lake: Factor w/ 3 levels "EVANS","JOLLIET",..: 3 3 3
3 3 3
> 3 3 3 3 ...
>  $ Age : int  1 1 1 1 1 1 1 1 1 1 ...
>  $ TL  : int  132 120 125 115 130 120 115 110 117 116 ...
>  $ W   : int  10 10 10 10 10 10 10 10 10 20 ...
>  $ Sex : Factor w/ 3 levels "F","I","M": 1 1
2 2 2 1 1 1 2 2 ...
>  $ WT  : num  0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23 ...
>  > fishdatameans=aggregate(fishdata$TL, list(Lake = 
> fishdata$Lake, Age=fishdata$Age), mean)
> 
> #  Now Age is a Factor but 10 is in the wrong position.
>  > fishdatameans$Age
>  [1] 0  1  1  1  2  2  2  3  3  3  4  4  4  5  5  6  6  6  7  8  9  10
> Levels: 0 1 10 2 3 4 5 6 7 8 9
> 
>  > as.numeric(fishdatameans$Age)
>  [1]  1  2  2  2  4  4  4  5  5  5  6  6  6  7  7  8  8  8  9 
> 10 11  3  >
> # What I want  is ---->   0  1  1  1  2  2  2  3  3  3  4  4  
> 4  5  5  
> 6  6  6  7  8  9  10
> 
> Bill
> 
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