$re = '/\b(?:Units?|Shops?|Offices?|Flats?|Rm|Rooms?|Suites?)[^,\r\n]+/i';
$str = 'Rm. 2301, Blk. B3-B4,
Flat/Room 5, 9/F,
rm A, 17/F.,
Flat F, 9/F,
Flat G1, 10/F,
Flat C, 36/F, Block 1,
Flat 1107&1108, 11/F,
Flat 2301, 23/F, F
Unit 3, 2/F, L
Unit 1603 16/F
Offices D-F, 23/F,
Office D-F, 23/F,
Unit 1901, 19/F,
Units A, 6/F,
Shop 14, G/F,
Rooms 2202,
Suite 702, 7/F.,
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php