php数组中怎么增加元素

$fruits = array('apple','pear','banana','orange');
array_unshift($fruits, 'cherry');
pr($fruits);

function pr($str){
    echo "<pre class="brush:php;toolbar:false">";
    print_r($str);
    echo "

Array(
    [0] => cherry
    [1] => apple
    [2] => pear
    [3] => banana
    [4] => orange
)

$fruits = array('apple','pear','banana','orange');
array_unshift($fruits, 'cherry','pie');
pr($fruits);

Array(
    [0] => cherry
    [1] => pie
    [2] => apple
    [3] => pear
    [4] => banana
    [5] => orange
)

$arr = array();
array_push($arr, e1, e2 ... en);

$fruits = array('apple','pear','banana','orange');
//第三个参数固定为0，第二个参数为插入的索引位置,最后一个参数是插入的元素，如果插入多个，写成数组
array_splice($fruits,3,0,'pie');
pr($fruits);

Array(
    [0] => apple
    [1] => pear
    [2] => banana
    [3] => pie
    [4] => orange
)

$fruits = array('apple','pear','banana','orange');
$new_items = array('pie','pie2');
array_splice($fruits,3,0,$new_items);
pr($fruits);

Array(
    [0] => apple
    [1] => pear
    [2] => banana
    [3] => pie
    [4] => pie2
    [5] => orange
)