Hi
I have a question (which may be an obvious one). It is about an idiom which I
have seen quite often:
o <- order(x); <- x[o]
vs. the alternative
x <- sort(x)
I am just wondering as to the rationale behind the order/reindex idiom vs
sorting. Especially as there seems to be a marked performance difference
(especially for integer vectors):
> x <- trunc(runif(1E6, 1, 100))
> system.time(y <- x[order(x)])
user system elapsed
1.19 0.01 1.21
> system.time(y <- sort(x))
user system elapsed
0.22 0.00 0.22
I suspect that the propensity for the order/reindex idiom may be related to
memory or space performance then, rather than time? Can anyone confirm if this
is the case?
Cheers
Rory
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