python - __getitem__ and __setitem__ not being called -

i have following class definition:

class codes():     def __new__(self, inp):         self.data = np.zeros((50,50))         self.capacity = 50         self.size = 6         self.data[:self.size,:self.size] = inp         self.x = 0         self.y = 0          return self      def __setitem__(self,coords,value):         x = coords[0]         y = coords[1]         if max(x,y) >= self.capacity:             self.capacity *= 2             newdata = np.zeroes((self.capacity,))             newdata[:self.size,:self.size] = self.data             self.data = newdata          self.data.__setitem__(coords,value)          if max(x,y) >= self.size:             print("expanding")             self.size = max(x,y)         print ("debug")     def __getitem__(self,coords):         x = coords[0]         y = coords[1]         return self.data[x,y] 

the , set methods don't seem being called. i'm initialising with:

inp = np.array([[20151125,18749137,1728984,30943339,10071777,33511524],                [31916031,21629792,16929656,7726640,15514188,4041754],                [16080970,8057251,1601130,7981243,11661866,16474243],                [24592653,32451966,21345942,9380097,10600672,31527494],                [77061,17552253,28094349,6899651,9250759,31663883],                [33071741,6796745,25397450,24659492,1534922,27995004]]) = codes(inp) 

if try execute print(a[1,1]), error:

traceback (most recent call last):   file "c:/users/cotont/dropbox/advent of code/advent of code 25-1.py", line 55, in <module>     print(a[1,1]) typeerror: 'type' object not subscriptable 

if try execute a[49,49] = 1, get:

traceback (most recent call last):   file "c:/users/cotont/dropbox/advent of code/advent of code 25-1.py", line 55, in <module>     a[49,49] = 1 typeerror: 'type' object not support item assignment 

why custom methods not being called, , how fix it?

you misunderstanding __new__ or accidentally used should have used __init__. returning codes object itself returning self:

def __new__(self, inp):     # ...     return self 

__new__ called static method on class , expected produce new instance in method.

because returned type object (the class), __getitem__ , __setitem__ looked on type (the default metaclass) (see special method lookup), fails.

you wanted use __init__ there instead; __init__ called on already-created instance:

class codes():     def __init__(self, inp):         self.data = np.zeros((50,50))         self.capacity = 50         self.size = 6         self.data[:self.size,:self.size] = inp         self.x = 0         self.y = 0 

__init__ doesn't need return (and returns ignored anyway), can drop return self line altogether.

if feel must use __new__ (perhaps because subclassing immutable type), @ least create instance super().__new__():

class codes():     def __new__(cls, inp):         instance = super(codes, cls).__new__(cls)         instance.data = np.zeros((50,50))         instance.capacity = 50         instance.size = 6         instance.data[:self.instance,:instance.size] = inp         instance.x = 0         instance.y = 0         return instance 

but using __init__ instead simpler.