Hash default -- what's going on here?

[Strangely this thread has completely disappeared from our server!
However I read this response on Google, and just had to reply!]

···

"Kroeger, Simon (ext)" <simon.kroeger....@siemens.com> wrote:

maybe
listA=["line1","line2","line3"]
listB=["line5","line3","line4"]
puts(listA & listB)
#=> line3

Ooh, yes! Isn't ruby a cute language...!

Thanks for jolting my preconceptions!

          -- Pete --