[R] sorting ascending descending! & THX@coling

[Peter Dalgaard BSA]

Thomas Vogels <tov at ece.cmu.edu> writes:

> Witold Eryk Wolski <wolski at molgen.mpg.de> writes:
> 
> > THX.
> > You are right!!
> > 
> > 
> >  a[order(-1*a)]
> > [1] 110  23   4   3   2
> > 
> > 
> > Eryk
> 
> hmm, I would have thought rev(order(...)) to be more intuitive:
> 
> x[order(x)] sorts in ascending order,
> x[rev(order(x))] sorts in descending order...

It is, but the sign trick generalizes to multiple sort criteria:

d[order(d$sex,-d$year,-rank(d$ch)),]

(assuming that d$ch is a character vector which you want to sort by in
reverse alphabetical order).

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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