[python] TypeError: 'NoneType' object has no attribute '__getitem__'

I'm having an issue and I have no idea why this is happening and how to fix it. I'm working on developing a Videogame with python and pygame and I'm getting this error:

 File "/home/matt/Smoking-Games/sg-project00/project00/GameModel.py", line 15, in Update 
   self.imageDef=self.values[2]
TypeError: 'NoneType' object has no attribute '__getitem__'

The code:

import pygame,components
from pygame.locals import *

class Player(components.Entity):

    def __init__(self,images):
        components.Entity.__init__(self,images)
        self.values=[]

    def Update(self,events,background):
        move=components.MoveFunctions()
        self.values=move.CompleteMove(events)
        self.imageDef=self.values[2]
        self.isMoving=self.values[3]

    def Animation(self,time):
        if(self.isMoving and time==1):
            self.pos+=1
            if (self.pos>(len(self.anim[self.imageDef])-1)):
                self.pos=0
        self.image=self.anim[self.imageDef][self.pos]

Can you explain to me what that error means and why it is happening so I can fix it?

This question is related to python typeerror

The answer is


The function move.CompleteMove(events) that you use within your class probably doesn't contain a return statement. So nothing is returned to self.values (==> None). Use return in move.CompleteMove(events) to return whatever you want to store in self.values and it should work. Hope this helps.


BrenBarn is correct. The error means you tried to do something like None[5]. In the backtrace, it says self.imageDef=self.values[2], which means that your self.values is None.

You should go through all the functions that update self.values and make sure you account for all the corner cases.


move.CompleteMove() does not return a value (perhaps it just prints something). Any method that does not return a value returns None, and you have assigned None to self.values.

Here is an example of this:

>>> def hello(x):
...    print x*2
...
>>> hello('world')
worldworld
>>> y = hello('world')
worldworld
>>> y
>>>

You'll note y doesn't print anything, because its None (the only value that doesn't print anything on the interactive prompt).