[R-sig-Geo] help to change value in a Data.frame

[Lyndon Estes]

Hi Gianni,

Try this

mydf[mydf$value < 0, "value"] <- 100

or this

mydf[mydf$value %in% c(-4, -5), "value"] <- 100

Cheers, Lyndon


On Tue, May 10, 2011 at 12:30 PM, gianni lavaredo
<gianni.lavaredo at gmail.com> wrote:
> Dear researchers,
>
> sorry I know it's no the right mailist but I have this problem.
>
> mydf <- data.frame(id=c(1,2,3,4,5),value=c(2,3,-5,6,-4))
>  id value
> 1  1     2
> 2  2     3
> 3  3    -5
> 4  4     6
> 5  5    -4
>
> I wish to select and change the value of negative number
>
> mydf[mydf$value >= -4 & mydf$value <= -5, c(2)] <- 100
>
> to have
>
>  id value
> 1  1     2
> 2  2     3
> 3  3    100
> 4  4     6
> 5  5    100
>
> but the normal expression doesn't work because they are negative value
>
> thanks in advance
> Gianni
>
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>
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-- 
Lyndon Estes
Research Associate
Woodrow Wilson School
Princeton University
+1-609-258-2392 (o)
+1-609-258-6082 (f)
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lestes at princeton.edu