This also works (giving a matrix so use as.data.frame if you want it
as a data frame):
> tapply(dat.long[,3], dat.long[1:2], c)
year
firm 2002 2003 2004 2005 2006
0 NA NA 1.0000000 NA NA
1 0.86456075 -1.06794272 1.1850129 -0.1385206 -0.41101249
2 0.04505626 0.24331227 -0.7902969 0.6833840 0.17823240
3 -2.07018155 0.32203467 -1.0867019 1.1990902 -0.86256005
4 -1.04872782 -0.90006314 1.0398810 -0.3545491 -0.93241925
5 -1.55728162 0.98297102 1.0280005 1.6397312 0.79278075
6 0.21446824 0.10913775 1.1284486 -0.4148321 0.95917517
7 -1.97895845 -0.05366712 0.9740745 0.8070221 1.33701029
8 -1.94635463 -1.03172741 1.5351331 -2.0643955 0.63561387
9 -0.08866245 0.42450753 -0.8108118 0.5155799 -1.54716628
10 0.11008895 0.18344337 0.3891310 0.9016668 0.04618046
On Sat, Jan 23, 2010 at 8:25 AM, ivo welch <ivo...@gmail.com> wrote:
> thank you, dennis. your example was much better than my own, too.
>
> for everyone else's benefit who will be searching for the answers for
> this problem on r-help, let me extend this a little. the problem
> arises primarily in data sets that are sparse. in my case, the first
> (ordered) firm does not have data in the first (ordered) year.
>
>> firm <- c(0,rep(1:10, each = 5))
>> year <- c(2004,rep(2002:2006, 10))
>> resp <- c(1.0,rnorm(50))
>> dat.long <- data.frame(firm = firm, year = year, resp = resp)
>> dat.wide <- reshape(dat.long, direction = 'wide', idvar = 'firm', timevar=
>> 'year')
>> head(dat.wide)
>
> yields
>
> firm resp.2004 resp.2002 resp.2003 resp.2005 resp.2006
> 1 0 1.0000 NA NA NA NA
> 2 1 -0.4483 -0.7623 1.0625 0.4654 -0.36041
> 7 2 -0.1373 -0.8648 0.7272 0.1637 -0.09235
> 12 3 1.0835 0.4544 0.1577 -1.6991 -1.04559
> 17 4 1.1390 2.1633 -1.2298 0.9460 -0.28682
> 22 5 -0.8906 1.0084 -0.1948 -0.6801 -0.47192
>
>
> in contrast, the library(reshape) function did yield the desired order:
>
>> library(reshape)
> Loading required package: plyr
>> dat.cast <- cast(dat.long, firm ~ year)
> Using resp as value column. Use the value argument to cast to
> override this choice
>> head(dat.cast)
> firm 2002 2003 2004 2005 2006
> 1 0 NA NA 1.0000 NA NA
> 2 1 -0.7623 1.0625 -0.4483 0.4654 -0.36041
> 3 2 -0.8648 0.7272 -0.1373 0.1637 -0.09235
> 4 3 0.4544 0.1577 1.0835 -1.6991 -1.04559
> 5 4 2.1633 -1.2298 1.1390 0.9460 -0.28682
> 6 5 1.0084 -0.1948 -0.8906 -0.6801 -0.47192
>
>
> I think this example would make a nice addition to "?reshape". for
> "see also", I would add library(reshape). finally, it would be nice
> if an email would be on each R help (in R documentation) to make
> suggestions for improvements.
>
> regards,
>
> /iaw
> ----
> Ivo Welch (ivo.we...@brown.edu, ivo.we...@gmail.com)
>
> ______________________________________________
> 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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