PHP 統計二維數組某個值有幾個?
PHP 計算二維數組某個值出現的次數
$list = [
['id' => 1, 'userId' => 5],
['id' => 2, 'userId' => 5],
['id' => 3, 'userId' => 6],
];
$userId = 5;
$arr=array_column($list,'userId');//把值提取出來轉成一維數組
$arr=array_count_values($arr);//數組的值作爲鍵名,該值在數組中出現的次數作爲值
echo $arr[$userId];//結果2