- array_fill_keys: documentation ( source)
- range: documentation ( source)
<?php
$data = array_fill_keys(range(100000, 200000), array_fill_keys(range('a', 'z'), 'plid'));
$headerKey = 'y';
$plids = array();
foreach ($data as $key => &$row)
{
if (isset($row[$headerKey]))
{
$plids[] = $row[$headerKey];
}
}