3v4l.org

run code in 300+ PHP versions simultaneously
<?php function generateUserFIO(array $names) { return implode( ' ', [ ucfirst(strtolower($names['last_name'])), (substr($names['first_name'], 0, 1) . '.'), (substr($names['middle_name'], 0, 1) . '.'), ] ); } print_r(generateUserFIO([ 'last_name' => 'Гопкало', 'first_name' => 'Никита', 'middle_name' => 'Владимирович', ])) . PHP_EOL; function generateUserFIO2(array $names) { return implode( ' ', [ ucfirst(strtolower($names['last_name'])), (substr($names['first_name'], 0, 2) . '.'), (substr($names['middle_name'], 0, 2) . '.'), ] ); } print_r(generateUserFIO2([ 'last_name' => 'Гопкало', 'first_name' => 'Никита', 'middle_name' => 'Владимирович', ]));

preferences:
35.6 ms | 402 KiB | 5 Q