Message-ID: <4AFA7DAA.4090203@statistik.tu-dortmund.de>
Date: 2009-11-11T09:02:34Z
From: Uwe Ligges
Subject: Re moving levels of a factor
In-Reply-To: <26297130.post@talk.nabble.com>
Dieter Menne wrote:
>
>
> Henrik Wahren wrote:
>> How can one or more levels be removed from a factor of a data frame. There
>> was a similar post on how to do this when a factor meets some criterion
>> (e.g. <= 2), but I can?t seem to get that solution to work.
>> Here, I simply want to drop some levels.
>>
>>
>
> Simply call factor again on the reduced set
>
> a = factor(c("a","b","b","b"))
> a[-1]
> factor(a[-1])
>
> If a is in a data frame, replace a by by df$a.
>
or a[-1, drop=TRUE]
Uwe Ligges
> Dieter