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<?php echo preg_replace_callback('/(_?[a-z]+)/', function($u) { var_dump($u); return ucwords(str_replace('_', '', $u[0])); } , 'rob_tr_yuui');
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
array(2) { [0]=> string(3) "rob" [1]=> string(3) "rob" } array(2) { [0]=> string(3) "_tr" [1]=> string(3) "_tr" } array(2) { [0]=> string(5) "_yuui" [1]=> string(5) "_yuui" } RobTrYuui
Output for 4.4.2 - 4.4.9, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17
Parse error: syntax error, unexpected T_FUNCTION in /in/pj0NT on line 6
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1, 5.0.0 - 5.0.5
Parse error: parse error, unexpected T_FUNCTION in /in/pj0NT on line 6
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error in /in/pj0NT on line 6
Process exited with code 255.

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