How to loop through an associative array and get the key?

You can do:

foreach ($arr as $key => $value) {
 echo $key;
}

As described in PHP docs.

If you use array_keys(), PHP will give you an array filled with just the keys:

$keys = array_keys($arr);
foreach($keys as $key) {
    echo($key);
}

Alternatively, you can do this:

foreach($arr as $key => $value) {
    echo($key);
}

Nobody answered with regular for loop? Sometimes I find it more readable and prefer for over foreach
So here it is:

$array = array('key1' => 'value1', 'key2' => 'value2'); 

$keys = array_keys($array);

for($i=0; $i < count($keys); ++$i) {
    echo $keys[$i] . ' ' . $array[$keys[$i]] . "\n";
}

/*
  prints:
  key1 value1
  key2 value2
*/