Associative arrays

I need to create an associative array with 20 students containing: enrollment, name and height. And show the top 5 students in the class, showing only student enrollment and height.

What is the best way to do this exercise?

Use the usort function to sort the array, the auxiliary function cmp defines which the ordering criterion and is displayed only the top five students.

$alunos = [
        ['nome' => "Doge", "matricula" => "M1", "altura" => 1.70 ],
        ['nome' => "João", "matricula" => "M2", "altura" => 1.90 ],
        ['nome' => "Pedro", "matricula" => "M4", "altura" => 1.50 ],
        ['nome' => "Mario", "matricula" => "M3", "altura" => 1.60 ],
        ['nome' => "A1", "matricula" => "M5", "altura" => 1.90 ],
        ['nome' => "A2", "matricula" => "M6", "altura" => 1.88 ]

];

function cmp($a, $b) {
    return $a["altura"] < $b["altura"];
}


usort($alunos, "cmp");

for($i=0; $i<5;$i++){
    echo $i .': '.  $alunos[$i]['nome'] .' - '.$alunos[$i]['altura'] .'<br>';
}

Output:

0: A1 - 1.9
1: João - 1.9
2: A2 - 1.88
3: Doge - 1.7
4: Mario - 1.6

A variation of the solution would use array_splice () to remove all items from the fifth position and use a foreach.

array_splice($alunos, 5);

foreach($alunos as $item){
    echo $item['nome'] .' - '. $item['altura'] .'<br>';
}