On the PHP::Impact blog today Federico points out five articles that can help you learn more about the Standard PHP Library, specifically in dealing with iterators.

When PHP 5 was initially released, it included a strong sense of standardization introduced in the core package. This can be a real time saver when common programming issues must be solved through proven, standard solutions. That's precisely the case with iterators, since the SPL package includes many predefined iterating classes that can be used for traversing different data structures, without having to reinvent the wheel over and over again.

The links include this article on phpro.org and this one on Zend's own site.