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Ouch!

by frankus (Priest)
on Sep 18, 2000 at 19:10 UTC ( #32960=note: print w/ replies, xml ) Need Help??


in reply to RE: shortest
in thread shortest

perl -ne's/$&&1?o:e/eg;print'

Okay this rocks and I've voted for your code... I think this is what's happening :

  1. perl -ne ''executes the one liner forever.
    1. the regexp substitutes each character using s/./ and /g.
    2. $& is the previous matches.
    3. &1 is evaluated in the trinary operator ? using /e.
    4. if &1 then replace with odd else replace with even
  2. print defaults to $_, the results of the regular expression.
but what I really wanna know is: what is &1?

Brother Frankus.


Comment on Ouch!
RE: Ouch!
by Adam (Vicar) on Sep 18, 2000 at 19:49 UTC
    &1 is the logical and applying the bit mask (1). Even numbers always end with a zero bit, odd always end with a 1 bit. This is a simple test for even/odd.
      Yup this I get, now ... how did I get a negative posting for asking a question? Is my appraisal wrong or does someone resent the ZX spectrum colours?

      Brother Frankus.

      Yup this I get, now ... how did I get a negative posting for asking a question? Is my appraisal wrong or does someone resent the spectrum colours?

      Brother Frankus.

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