[R] about sorting table
ligges at statistik.uni-dortmund.de
Thu Dec 1 10:33:07 CET 2005
Martin Maechler wrote:
>>>>>>"UweL" == Uwe Ligges <ligges at statistik.uni-dortmund.de>
>>>>>> on Thu, 01 Dec 2005 08:37:37 +0100 writes:
> UweL> herodote at oreka.com wrote:
> >> hi all,
> >> I load a table with headers that enable me to acces it by the column names:
> >> tab<-read.table("blob/data.dat",h=T)
> >> attach(tab)
> >> everythings are OK, but i try to sort this table against one of his column like this:
> >> tab<-tab[order(tab$IndexUI),];
> >> It is still ok, the table is sorted, if i type "tab" i see a sorted table.
> >> but, when i call the column by their names, it appears that the column isn't sorted...
> >> I believe that, is there a solution to attach column names another time, to reflect the effect of sorting this table?
> >> thks all for your answers
> UweL> see ?colnames
> eehm, that won't really help here.
> The problem is that Guillaume
> - first attach()ed the data frame
Ah, thank you, MArtin, I overlooked that line ....
> - then changed the data frame itself,
> - and then erronously assumed that the *attached* data would change.
> In general, we nowadays recommend quite often against using attach()
> but rather use the 'data = ' argument where applicable and use
> with( <data frame> , <......> )
> Martin Maechler, ETH Zurich
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