CODEWITHSUNDEEP
pythondictionary
Johnny
Johnny

Reputation: 205

Python Object in Dictionary Key Error

Im attempting to write a chess 'Swiss' tournament manager in Python. I have two classes, a match class and a player class. I also have two dictionaries, name_object, which binds a string name to an object, and name_score, which binds the Player object's name to the Player object's score (1.0, 2.5 etc.).

Variable Example

    name_object = {'Jim' : Object, 'Jack' : Object}
    name_score = {'Jim': 2.5, 'Jack' : 1.0}

My Classes

class Player:
    def __init__(self, name, gender, rating, score):
    self.name = name
    self.gender = gender
    self.rating = rating
    self.score = score

class Match:
    def __init__(self, white, black):
        self.white = white
        self.black = black

    def Result(self, res):
        global name_object, name_score
        complete = False
        if res == 1:
            if complete == False:
                name_object[self.white].score += 1
                name_score[self.white] += 1
                complete = True
        elif res == 0:
            if complete == False:
                name_object[self.black].score += 1
                name_score[self.black].score += 1
                complete = True
        elif res == 'd':
            if complete == False:
                name_object[self.white].score += .5
                name_score[self.white] += .5
                name_object[self.black].score += .5
                name_score[self.black].score += .5

but when I try to create an object with the two player names of 'Jim' and 'Jack', 

    Match1 = Match(name_object['Jim'], name_object['Jack'])

and then try to call the Result method with white winning,

    Match1.Result(1)

I get this error, 

    line 43, in Result
    name_object[self.white].score += 1
    KeyError: <__main__.Player object at 0x02AB6DF0>

All help is much appreciated

Upvotes: 2

Views: 5004

Answers (2)

Tim Peters
Tim Peters

Reputation: 70602

By eyeball, your name_object dict has strings for keys ('Jim' and 'Jack'). But your

name_object[self.white].score += 1

line (the one Python is complaining about) is not using a string to index name_object. It's using name_object['Jim'] (which is the undefined-in-the-code-you've-shown Object) to index that dict. That's why you're getting the KeyError: you're trying to index the dict using a key that's not in the dict.

How you fix it is up to you. I can't guess whether you want to use strings or instances of Player to index your dict.

Upvotes: 0

Veedrac
Veedrac

Reputation: 60147

self.white is set to name_object['Jim'], so when you do name_object[self.white] you are in effect searching the dict like

name_object[name_object['Jim']]

I very much doubt that that makes sense. You might want to consider passing 'Jim' alone in as self.white and then using name_object[self.white] in the rest of your code as appropriate.

Upvotes: 2

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