sub clear_it {
    my($data) = @_;
    $data = [];
    #@$data = ();
}
my $data = ['a','b'];
&clear_it($data);
print "size = ",($#$data + 1),"\n";

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This outputs "size = 2". If I use the second way of clearing the contents of the array (commented out), then that works as expected "size = 0".

This seems like a perl idiosyncrasy. Is there a simple explanation for this?

In reply to Pass array, then clear by Anonymous Monk

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