php 计算二维数组某个值出现的次数 2022-06-15

$list = [
    ['id' => 1, 'userId' => 5],
    ['id' => 2, 'userId' => 5],
    ['id' => 3, 'userId' => 6],
  ];
 
$userId = 5;
  
$arr=array_column($list,'userId');//把值提取出来转成一维数组
$arr=array_count_values($arr);//数组的值作为键名，该值在数组中出现的次数作为值
echo $arr[$userId];//结果2