my %hash = (
    "apples   " => 4,
    "oranges   " => 5
    );

foreach my $words (keys %hash)
{
    my $elem = $hash{$words};
    delete $hash{$words};
    $words =~ s/\s*$//;
    $hash{$words} = $elem;
}
print %hash;


##</code><code>##

delete argument is not a HASH or ARRAY element or slice at hashdel.pl line 5.