[R] create new column to combine 2 data.frames

[Rui Barradas]

Hello,

Suposing that your data frames are named dat1 and dat2, the following 
works, but it's a bit complicated, maybe there are simpler solutions.



dat1 <- read.table(text = "
ID Name
1  Jack
2  John
3  Jill
", header = TRUE, stringsAsFactors = FALSE)

dat2 <- read.table(text = "
ID  Days  Type
1    3       Training
2    1       Management
3    4       Training
", header = TRUE, stringsAsFactors = FALSE)

library(reshape2)
tmp <- dcast(data = dat2, ID ~ Type, value.var = "Type")

tmp[-1] <- lapply(tmp[-1], function(x){
	y <- integer(length(x))
	y[!is.na(x)] <- dat2[["Days"]][!is.na(x)]
	y})
result <- merge(dat1, tmp)
result


Hope this helps,

Rui Barradas

Em 30-08-2013 09:37, Mat escreveu:
> Hello together i have a little problem with the combine of two data.frames.
>
> I have 2 data.frames, which look like this one:
>
> first dataframe:
> ID Name
> 1  Jack
> 2  John
> 3  Jill
>
> second dataframe
> ID  Days  Type
> 1    3       Training
> 2    1       Management
> 3    4       Training
>
> At the end i want to create a data.frame like this one (the Type should be
> the new column and the entry of the column should be the days):
>
> ID Name  Training    Management
> 1  Jack    3            0
> 2  John    0            1
> 3  Jill       4            0
>
> maybe anyone can help me, how i can do this.
>
> Thanks a lot.
>
> Best regards. Mat
>
>
>
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