From murdoch at stats.uwo.ca  Thu Dec 22 05:24:05 2005
From: murdoch at stats.uwo.ca (Duncan Murdoch)
Date: Wed, 21 Dec 2005 23:24:05 -0500
Subject: [Rd] random output with sub(fixed = TRUE)
In-Reply-To: <43A9D3A2.6040103@jhsph.edu>
References: <43A9CB12.1020803@jhsph.edu> <x23bkmun5v.fsf@turmalin.kubism.ku.dk>
	<43A9D3A2.6040103@jhsph.edu>
Message-ID: <43AA2A65.9060009@stats.uwo.ca>

On 12/21/2005 5:13 PM, Roger D. Peng wrote:
> Well, who am I to break this long-standing ritual? :)
> 
> Interestingly, while the printed output looks wrong, I get
> 
>  > v <- paste(0:10, "asdf", sep = ".")
>  > a <- sub(".asdf", "", v, fixed = TRUE)
>  > b <- as.character(0:10)
>  > identical(a, b)
> [1] TRUE
>  >
> 
> -roger

I think finding two separate bugs on the day after the release goes a 
bit beyond what is necessary to satisfy the ritual.

Duncan Murdoch

> 
> Peter Dalgaard wrote:
> 
>>"Roger D. Peng" <rpeng at jhsph.edu> writes:
>>
>>
>>
>>>I've noticed what I think is curious behavior in using 'sub(fixed = TRUE)' and 
>>>was wondering if my expectation is incorrect.  Here is one example:
>>>
>>>v <- paste(0:10, "asdf", sep = ".")
>>>sub(".asdf", "", v, fixed = TRUE)
>>>
>>>The results I get are
>>>
>>>
>>>>sub(".asdf", "", v, fixed = TRUE)
>>>
>>> [1] "0"               "1\0st\0\0"       "2\0<af>\001\0\0" "3\0<af>\001\0\0"
>>> [5] "4\0mes\0"        "5\0<ba>\001\0\0" "6\0\0\0\0\0"     "7\0\0\0m\0"
>>> [9] "8\0\0\0t\0"      "9\0<fe>\0\0\0"   "10\0\0\0\0\0"
>>>
>>>I expected "0" in the first entry and everything else would be unchanged.  Your 
>>>results may vary since every time I run 'sub()' in this way, I get a slightly 
>>>different answer in entires 2 through 11.
>>>
>>>As it turns out, 'gsub(fixed = TRUE)' gives me the answer I *actually* wanted, 
>>>which was to replace the string in every entry.  But I still think the behavior 
>>>of 'sub(fixed = TRUE) is a bit odd.
>>>
>>>
>>>>version
>>>
>>>         _
>>>platform x86_64-unknown-linux-gnu
>>>arch     x86_64
>>>os       linux-gnu
>>>system   x86_64, linux-gnu
>>>status
>>>major    2
>>>minor    2.1
>>>year     2005
>>>month    12
>>>day      20
>>>svn rev  36812
>>>language R
>>>
>>
>>Argh... 
>>
>>year     2005
>>month    12
>>day      21
>>
>>and something like this gets discovered. It's a ritual, I tell ya, a ritual!
>>
>>If you look at the output and terminate all strings at the embedded
>>\0, it looks much more sensible, so it should be fairly easy to spot
>>the cause of this bug...
>>
> 
>



[Rd] random output with sub(fixed = TRUE)
Duncan Murdoch