pop @{$h->{'pop'}} shift @{$h->{'shift'}} map {1} @{$h->{'map {1}'}} grep {1} @{$h->{'grep {1}'}} chomp @{$h->{'chomp'}} lc @{$h->{'lc'}} Can't use an undefined value as an ARRAY reference at (eval 7) line 1. localtime @{$h->{'localtime'}} Can't use an undefined value as an ARRAY reference at (eval 8) line 1. cos @{$h->{'cos'}} Can't use an undefined value as an ARRAY reference at (eval 9) line 1. $VAR1 = { 'chomp' => [], 'pop' => [], 'map {1}' => [], 'grep {1}' => [], 'shift' => [] };