function preg_replace

[surion]

hi

 

for work i have to rewrite some stuf, now i find the next function in one of the files:

 

	function remove_accents( $string )
		{
		$string = htmlentities($string);
		$string = preg_replace("/&([a-z])[a-z]+;/i","$1",$string);
		$string = str_replace("-","",$string);
		$string = str_replace("'","",$string);	
		$string = str_replace(" ","",$string);	
		return $string;
		}

 

my question => i don't realy understand that preg_replace function, i know the first variable is a regular expression, and $string is the var where the regular expression should be ran on, but what is that $1 var doing there? since i don't know where it comes from, what it is, what it should be, what it does,... i don't know how to change it to make it work,...

and why is it in between quotes?

[Wildbug]

1) Check out the "Subpatterns" subsection of PCRE Pattern Syntax

 

2) The $1 variable contains the parenthetical, captured subpattern in the preceeding pattern.  That is, "([a-z])".  Whatever letter, if any, is captured there it will be accessible in the replacement string as either $1 (preferred) or \1.