計數陣列子單元

Question

我有以下多維數組：

Student Name Exam Result Exam Grade 
David 79 1H 
Brian 54 2H2 
Lisa 55 2H2 
Simone 58 2H2 
Francis 78 1H 
Shauna 53 2H2 
Sean 40 Pass 
Xavier 95 1H 
Tom 60 2H1 
Andy 66 2H2 

，我需要拿出寫一個函數來算多少次，每次 特定等級考試考內完成。例如3「1H's」已經實現。有任何想法嗎？

$exam = array ("names" => array ( "David", 
            "Brian", 
            "Lisa", 
            "Simone", 
            "Francis", 
            "Shauna", 
            "Sean", 
            "Xavier", 
            "Tom", 
             "Andy" 
            ), 
        "results" => array (79, 
             54, 
             55, 
             58, 
             78, 
             53, 
             40, 
             95, 
             60, 
             66 
            ), 
        "grades" => array ("1H", 
             "2H2", 
             "2H2", 
             "2H2", 
             "1H", 
             "2H2", 
             "Pass", 
             "1H", 
             "2H1", 
             "2H1" 
            ), 
       ); 

Answer 1

使用array_count_values

foreach(array_count_values($array['grades']) as $grade => $count){ 
    echo $grade.' achieved '.$count. ' times'.PHP_EOL; 
}