Online PHP editor | output for P1G20

<?php function do_split($name) { return preg_split('/([A-Z]{2,}|([A-Z][^A-Z]*))/', $name, null, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY); } function convert_case($name) { return implode( '_', array_map( 'strtolower', do_split($name) ) ); } function convert_case2($name) { $output = ''; foreach ($name as $char) { print_r("{$char} " . json_encode(ctype_upper($char))); } return strtolower($output); } convert_case2('FooBARbar'); $samples = array( 'FooBar', 'FooBAR', 'FOObar', 'foo_bar', 'FOO_bar', 'foo_BAR', 'foo_Bar', 'Foo_bar', ); /* print_r(array_map(function ($name) { return array( 'name' => $name, 'split' => do_split($name), 'converted' => convert_case($name), ); }, $samples)); */