get the avatar url instead of an html img tag when using get_avatar?

i want to get the user avatar URL to use it as background URL style for a div. i tried to use the following but it does not return anything when i view the code it appears like that.

background: url()

i used this function.

function get_avatar_url($get_avatar){
preg_match("/src="https://wordpress.stackexchange.com/questions/63198/(.*?)"/i", $get_avatar, $matches);
return $matches[1];
}

any help please??

It’s fairly simple to construct the Gravatar URL yourself, it’s just an MD5 hash of the user’s email address.

<?php $gravatar="http://www.gravatar.com/avatar/" . md5(strtolower($email)) . '&s=32'; ?>

<div class="avatar" style="background: url(<?php echo $gravatar ?>);" ></div>

The s parameter at the end there defines the size of the image in pixels.

Using Gravatars – WordPress Codex