Can a map be used in the 'def __init__' ? And how to read errors - oop

Question

I've created a class for a Counter that I'm wanting to build, and I want this object to figure out player scores. I'm expecting to see 3 when I test it, however what I get is the following error:
TypeError: unsupported operand type(s) for += 'method' and 'int' I'm not sure what that means, so I'm not sure if the issue is the map, my object itself, or my syntax. Any and all advice is welcome!
class Counter:
def __init__(self):
self.pointValue = {'Item_1': 3,
'Item_2': 5,
'Item_3': -3
}
def playerScore(self, itemFound ):
self.playerScore += (self.pointValue[itemFound])
return self.playerScore
gameCounter = Counter()
x = 'Item_1'
print (gameCounter.playerScore(x))

Answer 1

You can absolutely use a map (in Python it's called a dict) in __init__; it is not that part of the code that is throwing the error.
The message unsupported operand type(s) for += 'method' and 'int' refers to the line
self.playerScore += (self.pointValue[itemFound])
where self.playerScore is the method you are currently calling; it makes no sense to add an integer to a method, so an error is raised.
I think you actually want something like:
class ScoreCounter:
POINT_VALUE = {'Item_1': 3,
'Item_2': 5,
'Item_3': -3}
def __init__(self):
self.score = 0
def find_item(self, item):
self.score += self.POINT_VALUE.get(item, 0)
return self.score
Which you could use like:
>>> c = ScoreCounter()
>>> c.find_item("Item_1")
3
Note that the POINT_VALUE is a class attribute, shared by all ScoreCounter instances, whereas the score is an instance attribute, separate for each one. Also note that score is a different name to find_item, so you don't end up trying to assign to the method, and I have avoided the name Counter as it's used elsewhere. Finally, I have adopted naming conventions from the Python style guide.