Re: multi dimensional array question

thanks Piero! i was trying to solve an excercise on "learning php5" (O'reilyl) book. I am happy abotut his solution with the array_sum funtion you suggested, and my multidimensional array make much more sense to mee then they suggested solution that also much more line of code comapred... look: my solution (with Piero suggeston): and ont he bottom the book solution. what do u say is the best one? why? i am learning so i am interested in understanding why a solution can be better then an other... $us_census = array('NY' => array('New York' => 8008278), 'CA' => array('Los Angeles' => 3694820, 'San Diego' => 1223400), 'IL' => array('Chicago' => 2896016), 'TX' => array('Houston' => 1953631, 'Dallas' => 1188580, 'San Antonio' => 1144646), 'PA' => array('Philadelphia' => 1517550), 'AZ' => array('Phoenix' => 1321045), 'MI' => array('Detroit' => 951270)); print "<table><tr><th>State</th><th>City</th><th>Population</th><th>Total</th></tr>"; foreach ($us_census as $state => $cities) { foreach ($cities as $city => $habitants){ $tothabitants += $habitants; print "<tr><td>$state</td><td>$city</td><td>$habitants</td><td></td></tr>"; } } print "<tr><td></td><td></td><td></td><td>$tothabitants</td></tr></table>"; foreach ($us_census as $state => $cities) { $population_per_state = array_sum($cities); print "$state $population_per_state<br>"; } -------------------------- the book solution: $population = array('New York' => array('state' => 'NY', 'pop' => 8008278), 'Los Angeles' => array('state' => 'CA', 'pop' => 3694820), 'Chicago' => array('state' => 'IL', 'pop' => 2896016), 'Houston' => array('state' => 'TX', 'pop' => 1953631), 'Philadelphia' => array('state' => 'PA', 'pop' => 1517550), 'Phoenix' => array('state' => 'AZ', 'pop' => 1321045), 'San Diego' => array('state' => 'CA', 'pop' => 1223400), 'Dallas' => array('state' => 'TX', 'pop' => 1188580), 'San Antonio' => array('state' => 'TX', 'pop' => 1144646), 'Detroit' => array('state' => 'MI', 'pop' => 951270)); $state_totals = array( ); $total_population = 0; print "<table><tr><th>City</th><th>Population</th></tr>\n"; foreach ($population as $city => $info) { $total_population += $info['pop']; $state_totals[$info['state']] += $info['pop']; print "<tr><td>$city, {$info['state']}</td><td>{$info['pop']}</td></tr>\n"; } foreach ($state_totals as $state => $pop) { print "<tr><td>$state</td><td>$pop</td>\n"; } print "<tr><td>Total</td><td>$total_population</td></tr>\n"; print "</table>\n";