Re: multi dimensional array question

Thanks! I'll agree with you abotu ur points, i just started php few days ago..so i am in the first phase of learnign it...and this list is so gr8! thanks evrybody cheers, Nick On May 1, 2010, at 6:11 PM, Programming Guides wrote: > On Fri, Apr 30, 2010 at 7:33 PM, Nick Balestra <nick@beyounic.com> wrote: > 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"; > > > > > > I actually prefer your solution - it's easier to read and understand. On the other hand > the solution the book offers has the advantage of being more extensible in that more pieces of > information can be added per city. > > One thing I dont like about both solutions is that they both intertwine computation logic with > presentation. A *much* better approach in this case is to first calculate all population data you > need and put together one data structure that has all of that. Only after you have that ready do you > begin to output HTML. And while outputting HTML the only PHP you should need is to iterate over your > data structure and output. > > -- > http://programming-guides.com