PHP 数组 函数实例

$arr =explode(",",字符串); //explode字符串转换成数组  
空格字符窜是空格也可以转成数组
$arr =implode(",",数组); //implode数组转换成字符

//============返回数组中指定的一列=============================
array_column()   //array_column获取数组里面的某个字段转成一位维数组
实例：
$info= “select * from sb_htwy_articles where status=1 and picpath!='' ORDER BY createtime DESC limit 3”;   //只查询最新三条  //查询二维数组
$id = implode(',',array_column($info,'id'));    // 获取前三条id
//=======================================================

//=============计算二维数组里面的某个值总和===================
$text = array(
    array("dosage"=>5,"content"=>2),
    array("dosage"=>2,"content"=>2),
    array("dosage"=>2,"content"=>2),
);
$arr1 = array_column($text, 'dosage');  //一维数组，拿到自己想要计算的数组值
$total = array_sum($arr1);
print_r($total);die;
//====================================================


//===============判断$_POST['school_id']数组里面是否有重复的值======================
count($_POST['school_id']) != count(array_unique($_POST['school_id']))
$intersection = array_diff($arr,$school_ids); //取两个数组的差集 $arr是个数组和$school_ids另一个数组
//============================================================================

//============array_filter函数 将字串转成数组并过滤其中的空值=========================
$text = Array
(
    [0] =>
    [1] =>
    [2] =>
    [3] => 11
    [4] => 8, 9, 10
    [5] => 5, 7
    [6] => 4
    [7] => 2, 3, 12
    [8] =>
    [9] =>
)
$a = implode(",", $text)
print_r($a);
//打印出来为
$b=,,,118,9,10,5,7,4,2,3,12,,
$c =  array_filter(implode(",", $text)));
//=====================================================================================

//数组进行排序

$sort = array_column($nodes,'sort');
array_multisort($sort,SORT_ASC,$nodes);