一个问题正则表达式PHP

Question

Count character '_' in start line

example :

subject = '_abcd_abc';   // return 1
or 
subject = '__abcd_abc';  // return 2
or 
subject = '___abcd_abc';  // return 3

everyone help me ~ I use PHP

Answer 1

Try this:

return preg_match('/^_+/', $str, $match) ? strlen($match[0]) : 0;

If preg_match finds a match, $match[0] will contain that match and strlen($match[0]) returns the length of the match; otherwise the expression will return 0.