From james.lindsey@luc.ac.be  Thu Feb  1 09:56:07 2001
From: james.lindsey@luc.ac.be (james.lindsey@luc.ac.be)
Date: Thu, 1 Feb 2001 10:56:07 +0100 (MET)
Subject: [Rd] factors in data.frames (PR#835)
Message-ID: <200102010956.KAA29982@pubhealth.ku.dk>

The following seems to be a contradiction:

> df <- data.frame(x=gl(2,1,10))
> df[,1]
 [1] 1 2 1 2 1 2 1 2 1 2
Levels:  1 2 
> df[,1,drop=F]
   x
1  1
2  2
3  1
4  2
5  1
6  2
7  1
8  2
9  1
10 2
> is.factor(df[,1,drop=F])
[1] FALSE
> is.factor(df[,1])
[1] TRUE

with R1.2.1 both MS Windows and Intel RH5.2 versions.
 Jim

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[Rd] factors in data.frames (PR#835)
james.lindsey@luc.ac.be