Indexing bug?

On Wed, May 26, 2010 at 3:27 PM, Duncan Murdoch

Is this expected behaviour?

x <- factor(c("c", "b", "a","c"))
results <- c(c=4, b=5)
results[x]

giving

results[x]

<NA> ? ?b ? ?c <NA>
?NA ? ?5 ? ?4 ? NA

(i.e. it appears to give results[levels(x)]

I would say it gives

results[as.numeric(x)]

and it's not clear if that is less "expected". E.g., what happens if
results has no names? results[as.numeric(x)] would still work, but not
results[as.character(x)].

Factors have a dual nature (character labels vs numeric codes), and
when forced to choose, I think it's reasonable to choose the solution
which works more generally.

-Deepayan

whereas results[as.character(x)] does what I expected:

as.character(x)
results[as.character(x)]

as.character(x)

[1] "c" "b" "a" "c"

results[as.character(x)]

?c ? ?b <NA> ? ?c
?4 ? ?5 ? NA ? ?4

Duncan Murdoch

______________________________________________
R-devel at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel