3v4l.org

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<?php $re = '/([A-Z][a-z]*)(\d*[-+]?)/'; $str = 'K+ Cr7+ O2-'; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); print_r($matches);
Output for 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
Array ( [0] => Array ( [0] => K+ [1] => K [2] => + ) [1] => Array ( [0] => Cr7+ [1] => Cr [2] => 7+ ) [2] => Array ( [0] => O2- [1] => O [2] => 2- ) )
preferences:
110.13 ms | 1465 KiB | 4 Q