How to create a function in PHP that sorts an array based on one of its keys

Question

I have the following array:

$class = array(
        'e1' => array('nume' => 'Nitu', 'prenume' => 'Andrei', 'sex' => 'm', 'varsta' => 23),
        'e2' => array('nume' => 'Nae', 'prenume' => 'Ionel', 'sex' => 'm', 'varsta' => 27),
        'e3' => array('nume' => 'Noman', 'prenume' => 'Alice', 'sex' => 'f', 'varsta' => 22),
        'e4' => array('nume' => 'Geangos', 'prenume' => 'Bogdan', 'sex' => 'm', 'varsta' => 23),
        'e5' => array('nume' => 'Vasile', 'prenume' => 'Mihai', 'sex' => 'm', 'varsta' => 25)
);

What I would like to do is to create a function that can sort through this array based on one of its keys, for example I want the function to sort and output all the males ('sex' => 'm') from the array.

I have managed to do this with:

foreach ($class as $val) {
    if ($val['sex'] == 'm')
    echo $val['nume'].' '.$val['prenume'].'<br/>';
}

But I want to create a function of my own that can do just this, which would help me a lot and give me more insight on how functions work and how they should be done.

Answer 1

You're looking not for sorting your array, but for filtering it - feel the difference.

In PHP, there's array_filter() to do this. If you want to create flexible function, you can act like this:

function filterArray($data, $key, $value)
{
   return array_filter($data, function($row) use ($key, $value)
   {
      return $row[$key]==$value;
   });
}

$class = array(
        'e1' => array('nume' => 'Nitu', 'prenume' => 'Andrei', 'sex' => 'm', 'varsta' => 23),
        'e2' => array('nume' => 'Nae', 'prenume' => 'Ionel', 'sex' => 'm', 'varsta' => 27),
        'e3' => array('nume' => 'Noman', 'prenume' => 'Alice', 'sex' => 'f', 'varsta' => 22),
        'e4' => array('nume' => 'Geangos', 'prenume' => 'Bogdan', 'sex' => 'm', 'varsta' => 23),
        'e5' => array('nume' => 'Vasile', 'prenume' => 'Mihai', 'sex' => 'm', 'varsta' => 25)
);

$result = filterArray($class, 'sex', 'm');

Answer 2

Try this:

<?php
function array_sort($array,$search_key,$search_val){
    $re_array = array();
    foreach($array as $value){
        if($value[$search_key] == $search_val)
            $re_array[] = $value;
    }
    return $re_array;
}
$class = array(
        'e1' => array('nume' => 'Nitu', 'prenume' => 'Andrei', 'sex' => 'm', 'varsta' => 23),
        'e2' => array('nume' => 'Nae', 'prenume' => 'Ionel', 'sex' => 'm', 'varsta' => 27),
        'e3' => array('nume' => 'Noman', 'prenume' => 'Alice', 'sex' => 'f', 'varsta' => 22),
        'e4' => array('nume' => 'Geangos', 'prenume' => 'Bogdan', 'sex' => 'm', 'varsta' => 23),
        'e5' => array('nume' => 'Vasile', 'prenume' => 'Mihai', 'sex' => 'm', 'varsta' => 25)
);
$data = array_sort($class,'sex','m');
echo "<pre>";
print_r($data);
echo "</pre>";
exit;
?>