$re = '/((?:[\d]-?){7,})/m';
$str = 'import pandas as pd
df = pd.DataFrame({\'Text\':[\'This person num is 111-888-8780 and other\',
\'dont block 23 here\',
\'two numbers: 001-002-1234 and some other 123-456-7788 here\',
\'block this 666-666-6666\',
\'1-510-999-9999 is one more\'],
\'P_ID\': [1,2,3,4,5],
\'N_ID\' : [\'A1\', \'A2\', \'A3\',\'A4\', \'A5\']})
123-452';
preg_match_all($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