Try this:
DF$Index <- ave(1:nrow(DF), DF$Name, FUN = seq_along)
reshape(DF[-3], dir = "wide", idvar = "Name", timevar = "Index")
Also see the reshape package for another similar facility.
On Wed, May 13, 2009 at 2:02 AM, Dana Sevak <dana.se...@yahoo.com> wrote:
>
> Dear R Helpers,
>
> I have trouble applying reShape and reshape although I read the documentation
> and several posts, so I would very much appreciate your help on the two
> points below.
>
> I have a dataframe
>
> df = data.frame(Name=c("a", "a", "a", "b", "b", "c"), X1=c("12", "13", "14",
> "20", "25", "30"), X2 = c(200, 250, 300, 600, 700, 4))
>
>> df
> Name X1 X2
> 1 a 12 200
> 2 a 13 250
> 3 a 14 300
> 4 b 20 600
> 5 b 25 700
> 6 c 30 900
>
> First I need to add an additional column to this dataframe that will count
> the number of rows per each Name entry. The resulting df should look like:
>
> df.index = data.frame(Name=c("a", "a", "a", "b", "b", "c"), X1=c(12, 13, 14,
> 20, 25, 30), X2 = c(200, 250, 300, 600, 700, 4), Index=c(1,2,3,1,2,1))
>
>> df.index
> Name X1 X2 Index
> 1 a 12 200 1
> 2 a 13 250 2
> 3 a 14 300 3
> 4 b 20 600 1
> 5 b 25 700 2
> 6 c 30 900 1
>
> How can I do this?
>
>
> Secondly, I would like to reshape this dataframe in the form:
>
>> df2
> 1 2 3
> a 12 13 14
> b 20 25 NA
> c 30 NA NA
>
> Since the df is sorted by Name and X2, I would need that the available X1
> values populate the resulting rows in df2 from left to right (i.e. if only
> one value is available, it is written in the first column and the remaining
> columns get NAs). If I could generate the Index column, I think I could
> accomplish this with:
>
> df2 = reShape(df.index$X1, id=df.index$Name, colvar=df.index$Index)
> colnames(df2) = c("V1", "V2", "V3")
>
> However, is there a way to get to df2 without using the Index column and
> still have the NAs written as described above?
>
> Thank you so much for your help on these two issues.
>
> With best regards,
> Dana Sevak
>
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
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