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Re: Is this normal

by JavaFan (Canon)
on Jan 06, 2012 at 15:20 UTC ( #946612=note: print w/ replies, xml ) Need Help??

in reply to Is this normal

You're making two mistakes:

  1. You're calling the match in list context, so an empty list is returned, reducing the number of passed parameters.
  2. Even when called in scalar context, a non-match does not return 0. It returns the empty string (most Perl build-ins that return either a true or a false value, return 1 or "")

Comment on Re: Is this normal
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Re^2: Is this normal
by dave_the_m (Prior) on Jan 06, 2012 at 23:30 UTC
    a non-match does not return 0. It returns the empty string
    Strictly speaking, it returns PL_sv_no, which has both a numerical value of 0 and a string value of "":
    $ perl5140 -MDevel::Peek -e 'Dump scalar(/x/)' SV = PVNV(0x275ee10) at 0xa26500 REFCNT = 2147483647 FLAGS = (IOK,NOK,POK,READONLY,pIOK,pNOK,pPOK) IV = 0 NV = 0 PV = 0x275ee00 ""\0 CUR = 0 LEN = 16


      You are correct. However, the OP is printing out the values, so the string value will be taken.

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