Message-ID: <17294.48368.284665.980111@stat.math.ethz.ch>
Date: 2005-12-01T09:05:52Z
From: Martin Maechler
Subject: about sorting table
In-Reply-To: <438EA841.5010308@statistik.uni-dortmund.de>
>>>>> "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
- 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> , <......> )
otherwise.
Martin Maechler, ETH Zurich