I love regex. I’ve used them with grep, Perl, Java, C, and a variety of others. I have Jeffery Friedl’s awesome book on them, and I studied their theory in college.
But for years I have been haunted by a famous regex joke:
Q: What did one regular expression say to the other?
A: .*
which I first saw on Slashdot, years ago.
Could someone conclusively explain this one to me? I have seen this joke time and time again, but despite fully understanding regular expressions I do not get the punch line.
".*" matches everything. Other than that, I don't know what to tell you, it's not a very funny joke.
Maybe it means, whatever one regular expression said to another, it would be matched by .*
Maybe the joke is that regexes can't speak? I can't find anything else funny in there....
Supposed to represent emoticons??
See: http://turing.cs.camosun.bc.ca/CompTech/index.php?topic=389.0
Best translated as "Whatever!" (a common one-word occurrence in alleged "conversation" in certain age groups).
Note that usually the dot does not match everything. Think about newlines. In order to match those, you will need to enable “dot-matches-all” mode. In Perl and PCRE a /s modifier is available for that.
A typical exchange among adolescent regexes:
// # What's up, dude?
/.*/ # Whatever! (#)
! /./ # Not!
/[#!%$&*]+/ # Screw you!
(#) Borrowing Alex Martelli's fine answer.
it says... WHATEVER xD
since the * denotes any char alphanumeric in regex...
thanks for the funniest problem ever
What about this:
Since the question specifically reference two regexes ('one' and the 'other') - you could interpret it this way:
Regex one=/Q. What did one regex say to the other?/
Regex other=/.*/
Which could (weakly I admit and still not funny) make the answer :
'What did one regex say to the other?' (since '.*' would match the first regex).
Which would make it a bit like the famous 'Who's on first base?' joke...
OR perhaps:
Regex one=/Q. What did one regex say to the other? A. .*/
Regex other=/Q. What did one regex say to the other? A. .*/
That is , apply the whole thing as a regex, run against itself..which would make it a infinite recursion joke for which there is a known tradition (especially in acronynms such as 'GNU')...
And a bit like those birthday cards which have 'how to confuse an idiot, turn over': which upon doing so reveals the same message....
The weakness in the above explanations is that even though the question is a valid regex, just not a very likely one: the first explanation doesn't even really use it as a regex (just a string) and then second explanation possibly suffers from ambigiouty as it contains a '?'...
It's like when Cliff Claven was on Jeopardy and the final jeopardy answer was something that, despite having accumulated a ridiculous sum of money (all of which he had bet on that question) he was unable to answer. The question —well, answer— matched /^These three people \w+ed the .*./. He wrote, "Who are three people who have never been in my kitchen?"