Описание тега nsindexpath
The NSIndexPath class represents the path to a specific node in a tree of nested array collections in Objective-C. This path is known as an index path.
Each index in an index path represents the index into an array of children from one node in the tree to another, deeper, node. For example, the index path 1.4.3.2 specifies the path shown below:
iOS adds programming interfaces to the NSIndexPath class of the Foundation framework to facilitate the identification of rows and sections in UITableView objects. The API consists of a class method and two properties. The indexPathForRow:inSection: method creates an NSIndexPath object from row and section index numbers. The properties return the row index number and the section index number from such objects