From tlumley@u.washington.edu  Tue Jul 23 22:07:12 2002
From: tlumley@u.washington.edu (Thomas Lumley)
Date: Tue, 23 Jul 2002 14:07:12 -0700 (PDT)
Subject: sub() and gsub() (PR#1826)
In-Reply-To: <200207232023.WAA09833@pubhealth.ku.dk>
Message-ID: <Pine.A41.4.44.0207231354200.207848-100000@homer05.u.washington.edu>

On Tue, 23 Jul 2002 jerome@hivnet.ubc.ca wrote:

> Full_Name: Jerome Asselin
> Version: 1.5.1
> OS: linux redhat 7.2
> Submission from: (NULL) (142.103.173.179)
>
>
>
> gsub() return different answers depending on how the input
> variables were created. Here is an example of code that
> replicates the problem. The vectors y and yy appear to be
> the same, but gsub() doesn't return the same answer.
> It should remove all the blanks when I use the vector y,
> but it doesn't remove them all. I have also tested that
> the same problem occurs if sub() is used instead of gsub().
>
> x <- structure(c(1, 3, 4, 5), class = "factor",
>      .Label = c("1 ", "2 ", "3 ", "4", "5"))
> y <- as.character(x)
> y
> gsub(" ","",y)
>
> yy <- c("1 ","3 ","4 ","5 ")
> yy
> gsub(" ","",yy)
>
>

I can't reproduce this (1.5.1, Debian Linux). I get
> y
[1] "1 " "3 " "4 " "5 "
> yy
[1] "1 " "3 " "4 " "5 "
> gsub(" ","",y)
[1] "1" "3" "4" "5"
> gsub(" ","",yy)
[1] "1" "3" "4" "5"
>  identical(y,yy)
[1] TRUE
>  identical(gsub(" ","",y),gsub(" ","",yy))
[1] TRUE

There used to be a possible bug where the R length and C length of a
string would be different (PR#1724), which might cause that sort of thing,
but the known manifestations of it were removed in 1.5.1


	-thomas

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sub() and gsub() (PR#1826)
Thomas Lumley