I am currently studying CS50's Introduction to Artificial Intelligence with Python. I've encountered a line of code that doesn't make sense to me and I can't seem to find any resources online to explain this to me.
def contains_state(self,state):
return any(node.state == state for node in self.frontier)
This is a method in a Python class. What baffles me is how do I make sense of node.state == state for node in self.frontier?
My understanding of any() is that it checks if any of the element that is being iterated is True but how does the code above work?
Thank you very much for your kind help.
The code inside any is a generator object with boolean values (either True or False). While going through the for loop, if any node.state == state, contains_state returns True.
The advantage of using a generator over a list is that you don't have to iterate through every element if you find a node whose state is equal to the state you are looking for. Therefore, in some/most cases it will run faster.
If it goes through the entire loop and none of the nodes' states equals the state passed to contains_state, the function returns False. You can learn more about generators here.