Starting up with the last of the Lerner courses, I got.
Iterators and Generators.
Hopefully I get done with this and use the same intensity with actually writing code.
What shape will that take and how will I write about it? I have no clue
For now, notes follow.
Notes ** Part 1, Iterators **
If we run the iter function on something and it comes back with an iterator object, then it’s iterable; I can iterate on it. Behind scenes in a for loop, Python does something similar. It asks if the object that has to be looped over is iterable with iter. And then keeps doing next with it to get the next result/item, until it comes across a StopIteration which lets it know, that the values are exhausted and it can stop looping. The for loop is a very thin shell, that asks the appropriate questions of the iterator. But it is always the iterator that determines, what exactly is returned. iterable vs iterator iterable means that it can be put into a “for” loop in Python things like strings, lists, dictionaries, sets, files and objects (that I will soon create) that implement that iterator protocol. it responds positively to the iter function’s question, Are you iterable? It returns an iterator object instead of raising errors (TypeErrors in this case) an iterator is the object returned by the iterable, the thing on which the next function is run. it could be the original object (the iterable) itself. it could also be a seperate object returned by the iterable. when the iterator object is exhausted, it returns StopIteration these are what give us the values. How do I make my objects iterable? By implementing the iterator protocol the object must respond to iter, by returning an iterator object it should respond to the next function with values it should raise a StopIteration error, when it’s done. Best to create a helper class, pass the data to it and return that as the iterator instance. helps with state, since I can then use the same object and iterate over it multiple times independantly. ** Part 2, Generators **
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