To understand what yield does, you must understand what generators are. And before you can understand generators, you must understand iterables. Iterables When you create a list, you can read its items one by one. Reading its items one by one is called iteration: >>> mylist = [1, 2, 3] >>> for i in mylist: ... print(i) 1 2 3 mylist is an iterable. When you use a list comprehension, you create a li