[Rd] Proposal unary - operator for factors

Hadley Wickham hadley at rice.edu
Thu Feb 4 00:38:11 CET 2010

> It wouldn't make sense in the context of
>   vector[-factor]

True, but that doesn't work currently so you wouldn't lose anything.
However, it would make a certain class of problem that used to throw
errors become silent.

> Wouldn't it be better to allow order's decreasing argument
> to be a vector with one element per ... argument?  That
> would work for numbers, factors, dates, and anything
> else.  Currently order silently ignores decreasing[2] and
> beyond.

The problem is you might want to do something like order(a, -b, c, -d)



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