aaply on a data.frame is not consistent with apply

[jiho]

library("plyr")

d <- data.frame(x=runif(5), y=runif(5))
aaply(d, 1, mean)

I would have expected the result to be

aaply(as.matrix(d), 1, mean)

just as

apply(d, 1, mean)

i.e. simply treat the data.frame as an array since I use a*ply. Basically it seems to be doing some sort of contingency table with additional computaiton (i.e. the mean) from the data.frame, but I don't understand why it would do this from the documentation.

[hadley]

I think str(alply(d, 1, mean)) should illustrate the complication - the mean of a data frame is a mean. But something is still going wrong because the output appears to have an extra dimension

[jiho]

I guess you mean the mean of a data.frame is a data.frame. Indeed that is another complication, but the problem is the same with sum.

[hadley]

Currently, a*ply(df, 1, ...) is equivalent to d*ply(df, all vars, ...), when I think it should actually be equivalent to d*ply(df, rownames, ...).

[hadley]

Fixed in 282e350