Or even better (doh!)...
library(plyr)
> ddply(DF0, .(A, B), summarise, C = sum(C))
A B C
1 52 1 124
2 52 59 38
3 52 97 75
4 57 1 64
5 57 6 26
6 57 114 12
7 89 1 192
8 89 6 20
9 89 29 137
10 89 52 13
11 89 57 10
12 89 97 23
which means that aggregate(), summaryBy() in the doBy package and several
more functions/packages can do this quite easily.
Dennis
On Wed, Oct 20, 2010 at 3:21 AM, Dennis Murphy <[email protected]> wrote:
> Hi:
>
> Here's one way, although it can be improved a bit.
>
> d1 <- aggregate(C ~ A, data = subset(DF0, B == 1), FUN = sum)
> d2 <- subset(DF0, B != 1)
> # B not in d1, so need to replace it
> > d1
> A C
> 1 52 124
> 2 57 64
> 3 89 192
> d1$B <- rep(1, nrow(d1))
> d1 <- d1[, c(1, 3, 2)] # reorder columns to permit cbinding
> DF1 <- rbind(d1, d2)
> > DF1[order(DF1$A, DF1$B), ]
> A B C
> 1 52 1 124
> 19 52 59 38
> 20 52 97 75
> 2 57 1 64
> 26 57 6 26
> 24 57 114 12
> 3 89 1 192
> 21 89 6 20
> 31 89 29 137
> 4 89 52 13
> 5 89 57 10
> 6 89 97 23
>
> HTH,
> Dennis
>
>
> On Wed, Oct 20, 2010 at 2:42 AM, xtracto <[email protected]> wrote:
>
>>
>> Hello,
>>
>> I am trying to achieve something which I *think* is possible using rowsum,
>> but a little help should be useful:
>>
>> Consider the following dataframe DF0:
>> A B C
>> 89 1 140
>> 89 06 20
>> 89 29 137
>> 89 52 13
>> 89 57 10
>> 89 97 23
>> 89 1 37
>> 89 1 12
>> 89 1 3
>> 52 1 11
>> 52 1 31
>> 52 1 16
>> 52 1 6
>> 52 1 10
>> 52 1 13
>> 52 1 10
>> 52 1 25
>> 52 1 2
>> 52 59 38
>> 52 97 75
>> 57 1 14
>> 57 1 13
>> 57 1 14
>> 57 114 12
>> 57 1 23
>> 57 06 26
>>
>>
>> I need create a new dataframe containing the sums of all the rows where B
>> =
>> 1 for the different values of A, keeping the rows with other B values the
>> same. That is, for this data sample, the result I expect is something like
>> this (the order of the rows does not matter):
>>
>> A B C
>> 89 1 192 #From adding up: [140 + 37 + 12 + 3]
>> 89 06 20
>> 89 29 137
>> 89 52 13
>> 89 57 10
>> 89 97 23
>> 52 1 124 # From adding up: [11 + 31 + 16 + 6 + 10 + 13 + 10
>> + 25 + 2]
>> 52 59 38
>> 52 97 75
>> 57 1 64 #From adding up: [14 +13 +14 +23]
>> 57 114 12
>> 57 06 26
>>
>>
>> Now, I now it should be possible to first separate the data in two sets,
>> where
>> DF1 <- DF0[DF0$B != 1,]
>> DF2 <- DF0[DF0$B == 1,]
>>
>> Then I should apply sumrow to DF2 with some "group" vector, but I do not
>> know where to go from here.
>>
>> Can anyone help?
>> Thanks in advance!
>>
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/rowsum-tp3003551p3003551.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> [email protected] mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> 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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