random output with sub(fixed = TRUE)

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

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...

-- 
Roger D. Peng  |  http://www.biostat.jhsph.edu/~rpeng/