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run code in 300+ PHP versions simultaneously
<?php $str = "\n\n\nABC\n\nDEF\nGHI\n\n\nJKL"; preg_match_all('~\n+|.+\n?~', $str, $matches); print_r(array_map(function($i) {return strtr($i, "\n", "#");},$matches[0]));

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