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run code in 150+ php & hhvm versions
Bugs & Features
<?php echo strtolower(preg_replace('/([A-Z])/', '_$1', 'camelCaseString'));
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
camel_case_string