in reply to Can If-then conditions do ($a = $b = $c) type expressions?

$a == $b is 1, which is obviously not equal to 5. As was recommended, grep's probably the way to go. Or 

$h{$_}++ for( $a, $b, $c );
if( $h{$a} == 3 ) { ... }

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Update: Just as a clarification, that hash trick will only work for things that stringify to the same thing. So for example if $b = "5 ", it wouldn't work (even though 5 == "5 " is true).

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Re: Re: Can If-then conditions do ($a = $b = $c) type expressions?
by snafu (Chaplain) on Apr 25, 2002 at 17:04 UTC
    Ahhh....yes. It didn't occur to me that ($a == $b) actually evaluates to true or 1 vs the value that they are set to which now makes sense. Excellent! Although, I do think that this kind of operation would be a nifty one to have available. It probably would be difficult to impossible to implement though.

    _ _ _ _ _ _ _ _ _ _
    - Jim
    Insert clever comment here...

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[d/l]
      I don't know about easy to read but it can be done in a roundabout sort of way: 
      $a = 5;
$b = 5;
$c = 5;
if ((($a == $b ) + ($a -1)) == $c) { print "yes!!!\n"; }

      [download]
      or better yet: 
      # given three equal variables
if (($a == $b ) == ($b == $c)) { print "yes!!!\n"; }

# as pointed out by Sidhekin
# given three different variables
if (($a == $b ) == ($b == $c)) { print "yes!!!\n"; }

# still prints 'yes!!!\n'.  Why?
# both sides evaluate to false or 0, 
# and 0 == 0 evaluates to true

      [download]
      Again, I'm not saying I'd use this... ;0)

      Update: Thanks to Sidhekin for pointing out my misstep. It does work with 2 same and 1 different variable. ;0)



      Amel
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[d/l]
[select]

        $a = 5;
$b = 5;
$c = 5;
if ((($a == $b ) + ($a -1)) == $c) { print "yes!!!\n"; }

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        Amel is one dangerous monk {grin} ... observe:

        $a = 6;
$b = 5;
$c = 5;
if ((($a == $b ) + ($a -1)) == $c) { print "yes!!!\n"; }

        [download]

        # given three equal variables
if (($a == $b ) == ($b == $c)) { print "yes!!!\n"; }

        [download]

        Yeah, right, "given three equal variables". Given three different variables, however ... 

        $a = 6;
$b = 4;
$c = 5;
if (($a == $b ) == ($b == $c)) { print "yes!!!\n"; }

        [download]

        ++ for not saying you'd use this ;-)

        Update:... and here I had finally convinced myself Amel had to be joking ... oh well ...
        You're welcome to that ++ anyways — the joke is none the worse for being unintended ;)

        The Sidhekin
        print "Just another Perl ${\(trickster and hacker)},"

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[d/l]
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