__getitem__ a 2d array

ili 0
Viewed 27

I am getting a weird error when trying to make the getitem method.

My code is:

def __getitem__(self, item):
    
    if (self.shape[0] == 1):
        return self.values[item]
    else:
        x, y = item 
        return self.twoDim[x][y]

I can't see where my mistake is, when I try

assert my_array[1][0] == 4

I get this error under:

x, y = item
TypeError: cannot unpack non-iterable int object

Any idea what the problem is? Thank for any tips

class python
1 Answers

Doing array[0][1] is first passing 0 into the __getitem__ function, and then whatever the function returns, it passes [1] into that function. With your implementation, you cannot do this. You must input a tuple of values in the first __getitem__ function:

class Array:

    def __init__(self):
        self.shape = (2, 2)
        self.values = None
        self.twoDim = [[1, 2], [3, 4]]

    def __getitem__(self, item):
        print(f"{item=}")
        if (self.shape[0] == 1):
            return self.values[item]
        else:
            x, y = item
            return self.twoDim[x][y]

array = Array()
try:
    print(array[1][0])       # item=1
except TypeError:
    pass
print("------")              
print(array[1, 1] == 4)      # item=(1, 1)
                             # True
Tom McLean0
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