PHP implode array keys

Need to implode array keys in PHP? Here's the way to do it.

We will use two PHP functions for this. First, array_keys($array) to get the keys of the array, and second, implode($glue, $array) to join the keys.

Here's an example:

$arr = array('one' => 1, 'two' => 2, 'three' => 3);
$keys = array_keys($arr);
$str = implode(' ', $keys);
echo $str;

The result will be 'one two three'.