- array_map: documentation ( source)
- print_r: documentation ( source)
- implode: documentation ( source)
- array_filter: documentation ( source)
<?php
$test = array('key' => 'value');
print_r(implode(
array_map(
array_filter($test, function($key, $value){ return $value == 'value';}),
function($key, $value){ return $value; })
)
);