Perhaps something like
# Untested
library(plyr)
ddply(DATA, "Date", function(d) sum(d$lmb.cpue))
For example, on some fake data
DATA <- data.frame(class = rep(letters[1:5], each = 2), type =
rep(c("good", "bad"), 5), value = rnorm(10))
ddply(DATA, "class", function(d) sum(d$value))
If you want to send example data, it's best to send it with the
plaintext output of dput().
Michael
On Mon, Jan 30, 2012 at 12:16 PM, karengrace84 <kgfis...@alumni.unc.edu> wrote:
> I'm having trouble with some catch per unit effort data (CPUE, fisheries
> data). Some of the samples were "retained" and some "unretained," and they
> are entered as 2 separate entries for the same sampling event (Date and
> time). I want to calculate the total CPUE (so sum the "retained" and
> "unretained" number for each sampling event) and am having troubld doing so.
> Here's a sample of what my data.frame looks like now:
>
> Date lmb.cpue
> Disposition.of.Catch
> 1999-07-10 12:10:00 0.66666667 Unretained
> 1999-07-10 12:10:00 0.16666667 Retained
> 1999-07-14 11:22:00 0.83333333 Unretained
> 1999-07-14 11:22:00 0.55555556 Retained
> 1999-07-14 11:48:00 0.16666667 Unretained
> 1999-07-14 11:48:00 0.58333333 Retained
> 1999-07-14 13:56:00 0.57142857 Retained
> 1999-07-15 10:23:00 0.11111111 Retained
> 1999-07-22 12:03:00 0.33333333 Retained
> 1999-07-25 11:26:00 0.40000000 Unretained
> 1999-07-25 11:26:00 1.00000000 Retained
>
>
> And I would like to end up with:
>
> Date lmb.cpue
> 1999-07-10 12:10:00 0.83333333
> 1999-07-14 11:22:00 1.38888889
> 1999-07-14 11:48:00 0.75000000
> 1999-07-14 13:56:00 0.57142857
> 1999-07-15 10:23:00 0.11111111
> 1999-07-22 12:03:00 0.33333333
> 1999-07-25 11:26:00 1.40000000
>
> Thanks for any help you have to offer!
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/how-to-sum-multiple-data-entries-for-the-same-sampling-event-tp4341670p4341670.html
> Sent from the R help mailing list archive at Nabble.com.
>
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