[R] create new column in a DF according to values from another column

[Rui Barradas]

Hello,

'if' is not vectorized, it only uses the first value of the multiple 
condition. 'ifelse' is vectorized and in your case use nested ifelses.


DF <- data.frame(number=c(1,4,7,3,11,16,14,17,20,19),data=c(1:10))
v1 <- c(1,7,11,16)
v2 <- c(4,14,20)
v3 <- c(3,17,19)

DF$Station <- ifelse(DF$number %in% v1, "V1",
             ifelse(DF$number %in% v2, "V2", "V3"))


Hope this helps,

Rui Barradas

Em 26-09-2012 11:49, jeff6868 escreveu:
> Hi everyone,
>
> I have a small problem in my R-code.
>
> Imagine this DF for example:
>
> DF <- data.frame(number=c(1,4,7,3,11,16,14,17,20,19),data=c(1:10))
>
> I would like to add a new column "Station" in this DF. This new column must
> be automatically filled with: "V1" or "V2" or "V3".
> The choice must be done on the numbers (1st column).
>
> For example, I would like to have "V1" in the column "Station" in the rows
> where the numbers of the 1st column are: 1,7,11,16 ; then I would like to
> have "V2" in the rows where the numbers are: 4,14,20 and finally "V3" in the
> rows where the numbers are: 3,17,19.
>
> I'm trying with "if" and something like this, but it's not working yet:
> # For "V1":
> if(DF$number %in% c(1,7,11,16)) {test$Station=="V1"}
> # For "V2":
> ...
>
> So my final DF should look like this:
>
> FINALDF <- data.frame(number=c(1,4,7,3,11,16,14,17,20,19),data=c(1:10),
> Station=c("V1","V2","V1","V3","V1","V1","V2","V3","V2","V3"))
>
> Could someone help me to finish this?
>
> Thank you very much!!!
>
>
>
>
>
> --
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>
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