From tlumley@u.washington.edu  Wed Oct  9 22:21:58 2002
From: tlumley@u.washington.edu (tlumley@u.washington.edu)
Date: Wed, 9 Oct 2002 23:21:58 +0200 (MET DST)
Subject: problems with missing values created by conversion using as.matri (PR#2133)
Message-ID: <200210092121.XAA08874@pubhealth.ku.dk>

On Wed, 9 Oct 2002 gregory_r_warnes@groton.pfizer.com wrote:
> ------------------------------
>
> Create a very simple data frame containing an factor and a character vector
> each containing a missing value:
>
> 	> x <- data.frame( a=c("",NA), b=c(1,NA) )
>
> Conversion to a matrix treats the two missing values differently:
>

Yes, as.matrix.data.frame() uses format() to make character strings, and
it needs to check for NA as well

	-thomas



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problems with missing values created by conversion using as.matri (PR#2133)
tlumley@u.washington.edu