PHP - 计算数组中数量的最佳方法

Question

I'm running a foreach loop on an array of students, that have a key ['all_user_grades']. What is the best way to count the number of As,Bs,Cs,Ds,Es and fails for each student in the array.

Here's what my array looks like:

[11] => Array
        (
            [id] => 10
            [All_User_Grades] => A, A, D, A, E
        )

Here's what my foreach looks like so far:

foreach($user_grades as $k => $v){
        $aug = $v['All_User_Grades'];
        $all_user_grades_arr = explode(',', $aug);
}

Answer 1

You can use substr_count() for this like so

$As = substr_count($aug, 'A');
$Bs = substr_count($aug, 'B');
//etc

or, just like you already did, explode and use the array for calculation

$all_user_grades_arr = explode(',', $aug);
$grades = array('A' => 0, 'B' => 0', ...);
foreach ($all_user_grades_arr as $val) {
    $grades[ trim($val) ]++;
}

The trim() here is necessary to get rid of unnecessary whitespaces