# [R] conditional sum two dataframes

Fri Jul 27 01:53:03 CEST 2012

```Hello,

Try the following.

m <- unlist(months)
v <- unlist(values)

aggregate(v ~ m, FUN=sum)
tapply(v, m, sum)

Hope this helps,

Em 26-07-2012 18:49, jcrosbie escreveu:
> I have two data frames. One with a matrix of months and the other with a
> matrix of values. The two dataframes correspond to each other. I would like
> to sum up all the values in by month.
>
> What would be an efficient way to do this?
>
> a=C(2,3,5,2,3,5)
> b=c(2,6,3,2,6,3)
> c=c(2,6,7,2,6,5)
>
> months <- data.frame(a,b,c)
>
> a=C(200,345,5435,27456,3343,555)
> b=c(288,699,377,234,6354,33454)
> c=c(2345,6345,79678,245,676,5089)
>
> values <- data.frame(a,b,c)
>
>
>
>
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