// assuming your first array is $data.
$result = collect($data)
->whereIn('student_id', $list)
->groupBy('student_id')
->map(function ($group) {
    return $group->sum('score');
})
->toArray();

print_r($result);

输出将是：

Array
   (
      [a] => 20
      [b] => 10
      [c] => 10
   )

您可以在PHP中使用循环和条件语句的组合。

// Initialize empty array to store the sums
$sums = [];

// Iterate over the original array
foreach ($array as $item) {
    $studentID = $item["student_id"];
    $score = (int)$item["score"]; // Convert score to integer

    // Check if the student ID is in list
    if (in_array($studentID, $list)) {
        // If the student ID already exists in the sums array, add the score
        if (isset($sums[$studentID])) {
            $sums[$studentID] += $score;
        } 
        // If the student ID doesn't exist in the sums array, 
        // initialize it with the score
        else {
            $sums[$studentID] = $score;
        }
    }
}

// Print the sums
print_r($sums);

$scores = [];
foreach ($data as $student) {
    if (in_array($student['student_id'], $list)) {
        if (!isset($scores[$student['student_id']])) {
            $scores[$student['student_id']] = $student['score'];
        } else {
            $scores[$student['student_id']] += $student['score'];
          }
    
    }
}
print_r($scores);