$re = '/center=(-?\d+\.\d+)%2C(-?\d+\.\d+)/m';
$str = 'https://maps.googleapis.com/maps/api/staticmap?scale=1¢er=40.744221%2C73.982854&language=en&zoom=15&markers=scale%3A1%7Cicon%3Ahttps%3A%2F%2Fyelp-images.s3.amazonaws.com%2Fassets%2Fmap-markers%2Fannotation_32x43.png%7C40.744221%2C-73.982854&client=gme-yelp&sensor=false&size=315x150&signature=OjixVjNCwF7yLR5tsYw2fDRZ7bw';
preg_match_all($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