[R] Reshaping data with xtabs giving me 'extra' data

[Tony B]

Thank you for taking the time to reply Henrique. Although your
solution does take away the zeroes and replaces them with NA's (which
i prefer), it unfortunately seems to reduce all of the other scores to
just '1':

> x <- with(do.call(rbind, df.list), tapply(Score, list(Date, Show, Time), length))
> x[,,"13:30:00"]
           Being Human Doctor Who Red Dwarf
2010-01-19          NA         NA        NA
2010-01-20           1          1         1

This is the first time i think i've used tapply, and after doing a
little searching, i was able to take your sugestion to get the desire
result:

> x <- with(do.call(rbind, df.list), tapply(Score, list(Date, Show, Time), function(x) { x } ))
> x[,,"13:30:00"]
           Being Human Doctor Who Red Dwarf
2010-01-19          NA         NA        NA
2010-01-20           2          3         1

Cheers!
Tony Breyal




On 20 Jan, 16:37, Henrique Dallazuanna <www... at gmail.com> wrote:
> Try with tapply:
>
>  with(do.call(rbind, df.list), tapply(Score, list(Date, Time, Show), length))
>
>
>
> On Wed, Jan 20, 2010 at 10:20 AM, Tony B <tony.bre... at googlemail.com> wrote:
> > Dear all,
>
> > Lets say I have several data frames as follows:
>
> >> set.seed(42)
> >> dates <- as.Date(c("2010-01-19", "2010-01-20"))
> >> times <- c("09:30:00", "11:30:00", "13:30:00", "15:30:00")
> >> shows <- c("Red Dwarf", "Being Human", "Doctor Who")
>
> >> df1 <- data.frame(Date = dates[1], Time = times[1], Show = shows, Score = 1:3)
> >> df2 <- data.frame(Date = dates[1], Time = times[2], Show = shows, Score = 1:3)
> >> df3 <- data.frame(Date = dates[1], Time = times[4], Show = shows, Score = 1:3)
> >> df4 <- data.frame(Date = dates[2], Time = times[1], Show = shows, Score = 1:3)
> >> df5 <- data.frame(Date = dates[2], Time = times[2], Show = shows, Score = 1:3)
> >> df6 <- data.frame(Date = dates[2], Time = times[3], Show = shows, Score = 1:3)
> >> df7 <- data.frame(Date = dates[2], Time = times[4], Show = shows, Score = 1:3)
> >> df7
> >        Date     Time        Show Score
> > 1 2010-01-20 15:30:00   Red Dwarf     1
> > 2 2010-01-20 15:30:00 Being Human     2
> > 3 2010-01-20 15:30:00  Doctor Who     3
>
> > I would like to somehow reshape the data into a different format:
>
> >> df.list <- list(df1, df2, df3, df4, df5, df6, df7)
> >> my.df <- Reduce(function(x, y) merge(x, y, all=TRUE), df.list, accumulate=F)
> >> my.xtab <- xtabs(as.numeric(Score) ~ Date + Show + Time, data = my.df)
>
> > This is where my problem occurs. In Time = 13:30:00, there is now data
> > for "2010-01-19" which was not in any of my original data frames
> > above:
>
> >> # I do not want the zeros below
> >> my.xtab[,,"13:30:00"]
> >            Show
> > Date         Being Human Doctor Who Red Dwarf
> >  2010-01-19           0          0         0
> >  2010-01-20           2          3         1
>
> > Perhaps I am missing something in the way i call the xtabs function?
>
> > Thank you kindly for your time,
> > Tony Breyal
>
> > OS: Windows XP 64bit
> >> sessionInfo()
> > R version 2.10.0 (2009-10-26)
> > i386-pc-mingw32
>
> > locale:
> > [1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United
> > States.1252    LC_MONETARY=English_United States.1252
> > LC_NUMERIC=C                           LC_TIME=English_United States.
> > 1252
>
> > attached base packages:
> > [1] stats     graphics  grDevices utils     datasets  methods
> > base
>
> > loaded via a namespace (and not attached):
> > [1] tools_2.10.0
>
> > ______________________________________________
> > R-h... at r-project.org mailing list
> >https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> --
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
>
> ______________________________________________
> R-h... at r-project.org mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.