ikegami,
Your first and second are identical in function

Not according to my test: 

#!/usr/bin/perl
use strict;
use warnings;
my @array = (undef, undef);
print "foo\n" if defined @array;
print "bar\n" if grep defined , @array;
__END__
$ perl foo.pl
defined(@array) is deprecated at foo.pl line 5.
        (Maybe you should just omit the defined()?)
foo

$ perl -v
This is perl, v5.8.5 built for cygwin-thread-multi-64int

[download]

Cheers - L~R

In reply to Re^3: Check if array is null by Limbic~Region
in thread Check if array is null by Texan

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