- implode: documentation ( source)
- iterator_to_array: documentation ( source)
<?php
function chain($input) {
foreach ($input as $arr) {
foreach ($arr as $v) {
yield $v;
}
}
}
$it = chain([
['a', 'b'],
['c', 'd', 'e'],
['f', 'g', 'h', 'i']
]);
echo implode(', ', iterator_to_array($it));