php統(tǒng)計(jì)多維數(shù)組的元素個數(shù)

ytwman 發(fā)布于2019-07-01 12:36 / 2063人閱讀

摘要：一般情況下，使用可以直接統(tǒng)計(jì)數(shù)組的元素個數(shù)但是遇到二位數(shù)組的時候，我們想統(tǒng)計(jì)第二層的元素個數(shù)，這個時候可以使用函數(shù)的第二個參數(shù)，統(tǒng)計(jì)一維的所有元素，循環(huán)統(tǒng)計(jì)遍歷元素在的時候，函數(shù)會循環(huán)統(tǒng)計(jì)元素的個數(shù)，如果元素是個數(shù)組則數(shù)量會總數(shù)會增加元素?cái)?shù)

一般情況下，使用count可以直接統(tǒng)計(jì)數(shù)組的元素個數(shù)
$arr = [

"a",
"b",

];
echo count($arr);//2
但是遇到二位數(shù)組的時候，我們想統(tǒng)計(jì)第二層的元素個數(shù)，這個時候可以使用count函數(shù)的第二個參數(shù)，
count($arr, $mode = 0);$mode(0：統(tǒng)計(jì)一維的所有元素，1：循環(huán)統(tǒng)計(jì)遍歷元素)
在$mode=1的時候，count函數(shù)會循環(huán)統(tǒng)計(jì)元素的個數(shù)，如果元素$a是個數(shù)組則數(shù)量會總數(shù)會增加$a元素?cái)?shù)加1；
$arr = [

"a" => "b",
"c" => [
    "d",
],

];
echo count($arr, 1);//3("b",["d"],"d")
只要二維數(shù)組有規(guī)律，則可以很方便的統(tǒng)計(jì)二維的元素個數(shù)
$arr = [

"a" => [
    "d",
    "e",
],
"c" => [
    "d",
    "g",
],

];
echo count($arr, 1) - count($arr);//4
使用array_map也可以
$arrCount = 0;
$countFun = function($a) use(&$arrCount) {

$arrCount += count($a);
return $arrCount;

};
array_map($countFun,$arr);
echo $arrCount;
記住$arrCount一定要引用傳值
如果要統(tǒng)計(jì)三維數(shù)組的元素個數(shù)
$arr = [

"a" => [
   "b" => [
       "d",
       "e",
       "g",
   ],
],
"c" => [
    "d" => [
        "d",
        "g",
    ],
],

];
$arrCount = 0;
$countFun = function($a) use(&$arrCount) {

$arrCount += count($a, 1) - count($a);
return $arrCount;

};
array_map($countFun,$arr);
echo $arrCount;
如果要統(tǒng)計(jì)四維數(shù)組的元素個數(shù)
$arr = [

"a" => [
   "b" => [
       "d" => [
           "e",
           "g",
       ],
   ],
],
"c" => [
    "d" => [
        "d" => [
            "e",
            "g",
            "f"
        ],
    ],
],

];
$arrCount = 0;
$napFun = function($a) use(&$arrCount) {

$countFun = function($a) use(&$arrCount) {
    $arrCount += count($a, 1) - count($a);
    return $arrCount;
};
array_map($countFun,$a);
return $arrCount;

};
array_map($napFun,$arr);
echo $arrCount;
如果是統(tǒng)計(jì)3維或更高維度的建議使用遞歸的方法
$arr = [

"a" => [
    "b" => [
       "d" => [
           "e",
           "g",
       ],
    ],
],
"c" => [
    "d" => [
        "d" => [
            "e",
            "g",
            "f"
        ],
    ],
],

];
function arrCount($arr, &$arrCount, $level){

if(0 === $level){
    $arrCount += count($arr);
    print_r($arr);
}else{
    $level--;
    foreach($arr as $a){
        arrCount($a, $arrCount, $level);
    }
}

}
$count = 0;
$level = 3;
arrCount($arr,$count,$level);
echo $count;