$re = '/\b(price|rs)?\s*(\d+[\s\d.]*\s*?(pkg|k|m|(?:la(?:c|kh|k)|crore|cr)s?|l)\b\.?)/m';
$str = 'This should matchprice 5.6 lacincluding price(i.e price 5.6 lac) and rs 56 m. including rs (i.e rs 56 k rs 56 m) .
It will match normally if there is no price or rs written for example or 56 k or 8.8 crs. are correct matching.
It should not match5.6 lac (Should not match eitherrs 6 lac asas there is no spaces before 5.6
';
preg_match_all($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