- array_map: documentation ( source)
- array_combine: documentation ( source)
- array_keys: documentation ( source)
- array_walk: documentation ( source)
<?php
$array = array(0=>array('tekstJeden' => 'jakas wartosc'));
array_walk($array, function(&$i) { $i = array_combine(array_map('ucfirst', array_keys($i)), $i); });