help to change value in a Data.frame

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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
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

? ? ? ?[[alternative HTML version deleted]]

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Lyndon Estes
Research Associate
Woodrow Wilson School
Princeton University
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lestes at princeton.edu