[R] calculations with vectors of unequal length

[Jeremy Hetzel]

See ?merge.

df.1 <- data.frame(year=factor(rep(1:3,3)), level=rep(letters[1:3],3),
number=c(11:19))
df.2 <- data.frame(year=factor(c(1:5)), number=c(21:25))

df.3 <- merge(df.1, df.2, by = "year")
df.3$new <- with(df.3, number.x + number.y)


Jeremy




On Wednesday, April 27, 2011 7:30:13 AM UTC-4, E Hofstadler wrote:
>
> Hi there,
>
> this is probably simple but I can't seem to figure it out by myself...
>
> I have two dataframes (df.1 and df.2):
>
> df.1 <- data.frame(year=factor(rep(1:3,3)), level=rep(letters[1:3],3),
> number=c(11:19))
> df.2 <- data.frame(year=factor(c(1:5)), number=c(21:25))
>
> I would like to create a new variable df.1$new, which is supposed to
> be the sum of each element of df.1$number and those elements of
> df.2$number, where df.2$year equals df.1$year.
>
> What would be the most efficient way of doing this?
>
> Regards,
> EH
>
> ______________________________________________
> R-h... at r-project.org 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.
>
>