Duncan -
Indeed, this has now been well documented; I have called these
constructions "Schrödinger Facts", since they arise from a superposition of
truths in the training data that collapse into an untruth when observed.
https://sentientsyllabus.substack.com/p/chatgpts-achilles-heel
Now, the curious question is: why can it program. Why is its production of
R-syntax less vulnerable to this effect than a literature quote, or
reference? Maybe it has to do with the fact that in producing correct
syntax there is a ground truth - errors just will not run. But I'm not sure.
Regardless: it signals that we need a reinvigorated culture of validation.
Actually ChatGPT will happily make test data for you. Whisvh. in a way, it
judt did ;-)
Boris
On 2023-02-13, at 08:37, Duncan Murdoch <murdoch.dun...@gmail.com>
wrote:
I was wondering which anchor would match in the regular expression
"(a)|(b)" if both "a" and "b" matches the target string. What appears to
happen is that the first match wins, and that's how it is documented in
Python, but I was looking for docs on this in R.
As far as I can see, the ?regex help page doesn't resolve this. So just
for fun, I decided to ask ChatGPT, and got an interesting response. I
won't show the whole conversation here, but just some extracts:
---------------------------------------
Me: In a regular expression in R, if both "a" and "b" match, which does
"(a)|(b)" match? Please include authoritative references in your answer.
ChatGPT: [long answer about grep]
Me: In grep(), it doesn't matter which of a or b matches. It's only in
sub() or gsub() that it makes a difference. Do you know an authoritative
reference that discusses those functions?
ChatGPT: [long irrelevant answer about sub and gsub, with a reference
to "R Cookbook" by P. Teetor.]
Me: Teetor's book is not authoritative, and the other reference doesn't
discuss ambiguous alternation.
... finally we get to the interesting part ...
ChatGPT: I apologize for the mistake in my previous answer.
A more authoritative reference for the behavior of regular expressions
in R can be found in the official R documentation.
Regarding the behavior of ambiguous alternation, the regex section of
the manual "An Introduction to R" explains it as follows:
"When several alternatives are possible, the first alternative is
chosen, so it is important to specify alternatives in the order in which
they should be tried."
Here is the reference for the official R documentation:
"An Introduction to R" manual:
https://cran.r-project.org/doc/manuals/r-release/R-intro.html#Regular-expression-facilities
I hope this reference provides the information you were looking for.
---------------------------------------
All right, an authoritative answer! The only problem is that *it
doesn't exist*. There's no such anchor in that document. R-intro isn't a
very rapidly changing document, so I could look at every change recorded in
svn, and that section has *never* existed.
I guess ChatGPT is a pattern matching machine, and if such a question
had an answer, it would probably be in a location like that. (I would have
guessed a help page like ?regex instead of R-intro, but I had just told it
that answer was wrong.)
Duncan Murdoch
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
--
Boris Steipe MD, PhD
Professor em.
Department of Biochemistry
Temerty Faculty of Medicine
University of Toronto
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
