greek letters using strtoupper and strtolower

Solution

There is no reason mb_strtolower() and mb_strtoupper() shouldn’t work:

<?php

header('Content-Type: text/html; charset=utf-8');

echo mb_strtoupper('παπακωνσταντινου', 'UTF-8'); // ΠΑΠΑΚΩΝΣΤΑΝΤΙΝΟΥ
echo mb_strtolower('ΠΑΠΑΚΩΝΣΤΑΝΤΙΝΟΥ', 'UTF-8'); // παπακωνσταντινου

?>

Using mb_convert_case() is another option, specially if you want to mimic ucwords():

<?php

header('Content-Type: text/html; charset=utf-8');

echo mb_convert_case('παπακωνσταντινου', MB_CASE_UPPER, 'UTF-8'); // ΠΑΠΑΚΩΝΣΤΑΝΤΙΝΟΥ
echo mb_convert_case('ΠΑΠΑΚΩΝΣΤΑΝΤΙΝΟΥ', MB_CASE_LOWER, 'UTF-8'); // παπακωνσταντινου
echo mb_convert_case('παπακωνσταντινου', MB_CASE_TITLE, 'UTF-8'); // Παπακωνσταντινου

?>

http://stackoverflow.com/questions/1979787/need-to-search-a-content-which-is-in-greek-letters-using-strtoupper-and-strtolowe