#! perl -w
use strict;
local ($,=" - ", $\="\n");

my ($ave, @left, @right);
my @array = qw/ 1 2 3 4 5 6 7 8 9 10/;

$ave = do { $ave += $_ for (@array) } / scalar @array;
print $ave, int($ave); # << Both these print 0 (zero) .......

for (@array) {
	last if $_ < int($ave);    # << ...but the array <b>is</b> being split at the mean value.
	push( @left, shift @array );
}
print @left;
print @array;

__DATA__
#output
C:\test>180278
0 - 0
1 - 2 - 3 - 4 - 5
6 - 7 - 8 - 9 - 10