PHP array group in loop and create multi dimensional array

Question

I have an associative multi dimensional array as below

$data = array();
$data = Array ( 
    [0] => Array ( [class] => 1styear [branch] => IT [Exam]         


        

Answer 1

A one-liner in a loop!

foreach($data as $array){
        $grouped[$array["class"]][$array["branch"]][$array["Exam"]][]=array("student name"=>$array["student name"],"Bio"=>$array["Bio"]);
}

$grouped produces:

Array(
    [1styear] => Array(
        [IT] => Array(
            [SEM1] => array(
                [0] => array(
                    [student name] => Alex,
                    [Bio] => Good Boy
                ),
                [1] => array(
                    [student name] => Philip,
                    [Bio] => Programmer
                )
            ),
            [SEM2] => array(
                [0] => array(
                    [student name] => Martin,
                    [Bio] => Smart
                )
            )
        ),
        [Finance] => array(
            [SEM2] => array(
                [0] => array(
                    [student name] => Mike,
                    [Bio] => Sport Player
                )
            )
        )
    ),
    [2ndyear] => array(
        [Finance] => array(
            [SEM1] => array(
                [0] => array(
                    [student name] => Mark,
                    [Bio] => Intelligent
                )
            )
        ),
        [IT] => array(
            [SEM1] => array(
                [0] => array(
                    [student name] => Shaun,
                    [Bio] => Football Player
                )
            )
        )
    )
)

---

Your follow up case, was MUCH more fun/challenging. I had to knock the dust off of some functions I don't play with very often. Check this out:

"1styear","branch"=>"IT","Exam"=>"SEM1","student name"=>"Alex","Bio"=>"Good Boy"),
    array ( "class"=>"2ndyear","branch"=>"Finance","Exam"=>"SEM1","student name"=>"Mark","Bio"=>"Intelligent" ),
    array ( "class"=>"2ndyear", "branch"=>"IT","Exam"=>"SEM1","student name"=>"Shaun","Bio"=>"Football Player" ), 
    array ( "class"=>"1styear","branch"=>"Finance","Exam"=>"SEM2","student name"=>"Mike","Bio"=>"Sport Player" ), 
    array ( "class"=>"1styear","branch"=>"IT","Exam"=>"SEM2","student name"=>"Martin","Bio"=>"Smart"),
    array ( "class"=>"1styear","branch"=>"IT","Exam"=>"SEM1","student name"=>"Philip","Bio"=>"Programmer"  )
);
$class_keys=array_unique(array_column($data,"class"));  // create array of unique class values
$Exam_keys=array_unique(array_column($data,"Exam"));  // create array of unique Exam values
foreach($class_keys as $class_key){
    $i=0;  // "class" subarray index
    foreach($Exam_keys as $Exam_key){
        $q=array("class"=>$class_key,"Exam"=>$Exam_key);  // this array can have 1 or more pairs
        // create an array only of rows where $q's key-value pairs exist
        $qualifying_array=array_filter(
            $data,
            function($val)use($q){  
                if(count(array_intersect_assoc($val,$q))==count($q)){  // total pairs found = total pairs sought
                    return $val;
                }
            },
            ARRAY_FILTER_USE_BOTH
        );
        foreach($qualifying_array as $qa){  // push appropriate values into array
            $grouped2[$class_key][$i]["Exam"]=$qa["Exam"];
            $grouped2[$class_key][$i]["branch"][]=$qa["branch"];
        }
        if(isset($grouped2[$class_key][$i]["branch"])){  // ensure no duplicate values in "branch" subarray
            $grouped2[$class_key][$i]["branch"]=array_unique($grouped2[$class_key][$i]["branch"]);
        }
        ++$i;  // increment the index for each "class" subarray
    }
}
echo "
";
print_r($grouped2);
echo "
";

The output isn't identical to what you requested, but I think you were just showing what it should look like generally. If this isn't quite right, let me know.

array(
    [1styear]=>array(
        [0]=>array(
            [Exam]=>SEM1
            [branch]=>array(
                [0]=>IT
            )
        ),
        [1]=>array(
            [Exam]=>SEM2
            [branch]=>array(
                [0]=>Finance,
                [1]=>IT
            )
        )
    ),
    [2ndyear]=>array(
        [0]=>array(
            [Exam]=>SEM1
            [branch]=>array(
                [0]=>Finance,
                [1]=>IT
            )
        )
    )
)