preg_match - Why two identical items in matches

Question

$str = '<iframe src="https://www.google.com/maps/place/the-big-junky-map-url-with-lat-lon-etc-etc" width="100%" height="350" frameborder="0" style="border:0;" allowfullscreen></iframe>';
$matches  = array();
preg_match('/src\=\"((.*?))\"/i',$map, $matches);
echo '<pre>';print_r($matches);die();

I want to extract the URL from src attribute. And I get following in $matches.

Array
(
    [0] => src="https://www.google.com/maps/place/the-big-junky-map-url-with-lat-lon-etc-etc"
    [1] => https://www.google.com/maps/place/the-big-junky-map-url-with-lat-lon-etc-etc
    [2] => https://www.google.com/maps/place/the-big-junky-map-url-with-lat-lon-etc-etc
)

I got what I needed, but why are there two identical items at [1] and [2]? How can I avoid this?

Answer 1

Just remove the $map, use $str at preg_match('/src\=\"((.*?))\"/i',$map, $matches);. Stop using double capturing group of your result.

Try this

$str = '<iframe src="https://www.google.com/maps/place/the-big-junky-map-url-with-lat-lon-etc-etc" width="100%" height="350" frameborder="0" style="border:0;" allowfullscreen></iframe>';
$matches  = array();
preg_match('/src\=\"(.*?)\"/i',$str, $matches);

echo '<pre>';
print_r($matches);

Result

Array
(
    [0] => src="https://www.google.com/maps/place/the-big-junky-map-url-with-lat-lon-etc-etc"
    [1] => https://www.google.com/maps/place/the-big-junky-map-url-with-lat-lon-etc-etc
)