PHP 数组

$a = array();

$a[0] = 'a';
$a[1] = 1;
$a[10] = 5;
$a[1] = 2.4;

$a = array();
$a[0] = 'a0';
$a['f'] = 'af';
$a[2] = 'he';
$a[1] = 1;
$a[1.7] = '45';
$a['1.7'] = 'a1';
$a['ha'] = 'ahh';
$a['0'] = 'ahh';
print_r($a);
echo $a[1.7] . ' and ' . $a['1.7']. ' and ' . $a[0];

Array
(
    [0] => ahh
    [f] => af
    [2] => he
    [1] => 45
    [1.7] => a1
    [ha] => ahh
)
45 and a1 and ahh

$arr = array($a => $b[, ...])

array($a[, ...])

array_push($a, $b)