iterable vs iterator class instance is iterable if you can loop over the data stored in the instance the data may be stored in the different attributes and in ways not directly accessible bysayarray like indexing class must provide for an iterator in order for its instances to be iterable and this iterable must be returned by the definition of iter for the class commonlythe iterator defined for class will itself be class that provides implementation for method named next in python and next in python purdue university