undef $array[$i] 

##</code><code>##

my @array = qw( 1 2 3 4 );

print "there are ".scalar(@array)." elements in \@array \n";
print "the last index of \@array is $#array \n";
print "the 3'rd (index 2) value of \@array is  $array[2] \n";

undef $array[2];

print "\$array[2] is now undefined \n" if not defined $array[2];
print "there are STILL ".scalar(@array)." elements in \@array \n";
print "the last index of \@array is STILL $#array \n";