[R] tapply, data.frame problem

[Chuck Cleland]

Lauri Nikkinen wrote:
> Hi R-users,
> 
> I'm quite new to R and trying to learn the basics. I have a following
> problem concerning the convertion of array object into data frame. I have
> made following data sets
> 
> tmp1 <- rnorm(100)
> tmp2 <- gl(10,2,length=100)
> tmp3 <- as.data.frame(cbind(tmp1,tmp2))
> tmp3.sum <- tapply(tmp3$tmp1,tmp3$tmp2,sum)
> tmp3.sum <- as.data.frame(tapply(tmp1,tmp2,sum))
> and I want the levels from tmp2 be shown as a column in the data.frame, not
> as row name as it now does. To put it in another way, as a result, I want a
> data frame with two columns: levels and the sums of those levels. Row names
> can be, for example, numbers from 1 to 10.

aggregate(tmp3[1], tmp3[2], sum)
   tmp2        tmp1
1     1  8.41550650
2     2  3.65831086
3     3 -0.26296334
4     4  3.45368671
5     5 -4.64383794
6     6  0.25640949
7     7  0.02832348
8     8 -0.03811150
9     9  1.41724121
10   10 -1.06780900

?aggregate

> -Lauri Nikkinen
> Lahti, Finland
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Chuck Cleland, Ph.D.
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