[R] intervals from cut() as numerics?

[Gavin Simpson]

On Sat, 2006-05-20 at 15:44 +0200, Dimitrios Rizopoulos wrote:
> as an alternative, you can have a look inside cut.default and use the 
> part that produces the breaks, i.e.,
> 
> breaks <- 10
> groups <- cut(x, breaks = breaks)
> max.bias <- as.vector(tapply(error, groups, mean))
> 
> # from cut.default()
> nb <- as.integer(breaks + 1)
> dx <- diff(rx <- range(x, na.rm = TRUE))
> breaks <- round(seq(rx[1] - dx/1000, rx[2] + dx/1000, len = nb), 2)
> mat <- cbind(breaks[1:(nb - 1)], breaks[2:nb])
> 
> plot(x, error, type = "n")
> abline(h = 0, col = "grey")
> panel.smooth(x, error)
> arrows(mat[, 1], max.bias, mat[, 2], max.bias, length = 0.05, 
> angle = 90, code = 3)
<snip />

Thanks also to Dimitrios and Gabor for your suggests. This suggestion
from Dimitrios is probably the one I'll use even though all three
suggestions give the same end result. I like this one because it seems
(to me) better to do the calculations than process the text labels
assigned to the list names, and because this will end up in a package to
go on CRAN I'd prefer not to add dependencies if I can avoid it -
especially if an alternative is available.

All the best,

Gav
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Gavin Simpson
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