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<?php $examples = [ 'Sep 04-08', 'Sep 29-Oct 01', ]; $result = []; foreach ($examples as $example) { var_export( explode('-', preg_replace('/^(\D{4})\d{2}-\K(?=\d)/', '$1', $example)) ); echo "\n"; }

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44.43 ms | 402 KiB | 5 Q