Mumia W. wrote:
>
> That happens because the match variables ($1, $2, ...) are only changed
> when a regular expression matches; otherwise, they are left alone.
>
> In the first case, "$2 !~ /domain\.com/" succeeds but does not capture
> anything, so the numbered match variables are unset.
>
> Your situation reinforces the rule that you should always test if the
> match succeeded before you attempt to use the match variables:
>
> my $email = '[EMAIL PROTECTED]';
> my @f = (undef, $email =~ /(.*)\@(.*)/);
Why did you put undef in there? It serves no useful purpose other than making
the code harder to understand for beginners.
my @f = $email =~ /(.*)\@(.*)/;
> (@f > 1) && ($f[2] =~ /domain\.com/ ?
> print "$f[1]\n" : print "var 2 is bad\n" );
>
> The test "@f > 1" is my way of testing if the match succeeded.
The rvalue conditional operator should use the returned value:
print @f > 1 && $f[ 2 ] =~ /domain\.com/
? $f[ 1 ]
: 'var 2 is bad',
"\n";
John
--
Perl isn't a toolbox, but a small machine shop where you can special-order
certain sorts of tools at low cost and in short order. -- Larry Wall
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