Hi,

If I understood your question, maybe sth like this:

AnnualFireCount<-aggregate(ANY.OF.YOUR.VARIABLES~Fire_Year, length,
data=yukon)

you can put any variable name in your dataframe (eg Fire_Year) in the place
of ANY.OF.YOUR.VARIABLES as the function only counts them.


On Tue, Jun 14, 2011 at 2:19 AM, saba <Sa-Ba@gmx.net> wrote:

> Hello,
>
> I used R a year ago. With the data I am working with now, I realized that I
> need to go back to R. Unfortunately, my memory is not my friend if it comes
> down to coding :-)
>
> What I want to do is extract the length of a variable of a file with
> certain
> conditions and then print this number in a new variable..
>
> My file (yukon), contains information about fires in the Yukon Territory,
> and it looks basically like this:
>
> Fire_Year Area_Hecta InitialFir ... and other headers but they are not
> important
>
> The Fire_Year ranges from 1980-2010, the Area_Hecta contains numbers and
> the
> InitialFir contains a date written like this: 24/05/1980
>
> My end goal is to plot 2 plots, one with the summed area burned per year
> and
> the other plot should show the number of fires happening per year.
>
> I managed the first plot with the command aggregate.
>
> annualAB.sum<-aggregate(yukon$Area_Hecta~yukon$Fire_Year, sum, data=yukon)
>
> Now I am having troubles with the second plot. I created subsets for each
> year and then used the length command..then I could take all those numbers
> and put them in a new variable...
>
> y1980 <- subset(yukon,Fire_Year=="1980")
> length(y1980$Area_Hecta)
>
> but I somehow feel that there must be a better solution...maybe a loop?
>
> Any help is greatly appreciated
> Thanks so much
> Sandra
>
>
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Count-objects-and-print-it-into-a-new-variable-tp3595174p3595174.html
> Sent from the R help mailing list archive at Nabble.com.
>
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>



-- 
Majid Einian
PhD Candidate in "Economics"
Graduate School of Management and Economics
Sharif University of Technology

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