PHP数组追加元素

<?php$a_1 = array("200kg","200cm");$a_2 = array("20kg","20cm","ok");$a_3 = array("2kg","2cm","ko");$a_4 = array("1kg","1cm","hello","world");$a[] = $a_1;$a[] = $a_2;array_push($a,$a_3,$a_4);//array_push() 函数等于多次调用 $array[] = $value。//如果用 array_push() 来给数组增加一个单元，还不如用 $array[] =，因为这样没有调用函数的额外负担。//如果第一个参数不是数组，array_push() 将发出一条警告。这和 $var[] 的行为不同，后者会新建一个数组。print_r($a);输出结果：Array(    [0] => Array        (            [0] => 200kg            [1] => 200cm        )    [1] => Array        (            [0] => 20kg            [1] => 20cm            [2] => ok        )    [2] => Array        (            [0] => 2kg            [1] => 2cm            [2] => ko        )    [3] => Array        (            [0] => 1kg            [1] => 1cm            [2] => hello            [3] => world        ))