How do I get this to a numeric array

How do I get this user_meta data to a php array that I can get count and access values?
$share = array(); $share = user_meta['key];
echo "$share"; shows this result
a:4:{i:0;s:2:”22?;i:1;s:2:”23?;i:2;s:1:”2?;i:3;s:2:”16?;} but neither count($share) or $share[3] display anything on echo.
Thanks, boyd