I want to make this type of expandable/collapsible table vie
TLIndexPathTools can do this sort of thing naturally. In fact, there is are extensions for both expandable sections and expandable tree structures. Try running the Collapse sample project for expandable sections and the Outline sample project for expandable trees.
One advantage of using TLIndexPathTools is that, as a simple, low-level API, it can solve all kinds of dynamic table view and collection view problems using a common approach. And it works interchangeably with Core Data and plain arrays.