<?php
$car = array(
    ['id'=>612,'name'=>'bus','weight'=>300,'capacity'=>22],
    ['id'=>1580,'name'=>'taxi','weight'=>210,'capacity'=>5],
    ['id'=>300,'name'=>'coach','weight'=>550,'capacity'=>86],
);
print_r($car);
print $car[0]['capacity'];
$car[]=['id'=>105,'name'=>'motorbike','weight'=>100,'capacity'=>2];
$car[2]['name'] = 'truck';
$car[2]['weight'] = 350;
print_r($car[2]);
unset($car[0]['weight']);
unset($car[1]);
print_r($car);
echo "bus的承载量是".$car[0]['capacity'];


?>