Reshaping data with xtabs giving me 'extra' data

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

--
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O