Please Help w/Perl Script

I am trying to find every occurrence of a pattern within a string, and remove it. For example:

$string = "abcdabcdabcd";

and I want to remove every a so that $string = "bcdbcdbcd"

is there a function that does that? Or a simple way. I know I can use index() and loop through and do substr() etc...but is there a more eloquent solution?

$string=~s/a//g;

Also see: http://www.gossland.com/course/matching/advanced.html