How can I access objects from nested lists with a loop

Question

When looping through a nested list of objects with the standard for loop method I am receiving error AttributeError: 'list' object has no attribute 'val'

I'm looking for a way to return these values from the nested objects

class Class:
    def __init__(self,val,var_1 = True,var_2 = False,var_3 = True):
        self.val = val
        self.var_1 = var_1
        self.var_2 = var_2
        self.var_3 = var_3

    def print_num(self):
        return self.val


block = [[Class("O") for x in range(10)] for y in range(10)]

print(block[0][0].val) # this works returns "O" or correct var bool value

for x in block:        #This doesn't work 
    print(x.val)

['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']
['O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O', 'O']

Looking for this return, or similar

Elbattore · Accepted Answer · 2019-07-17 09:01:57Z

3

the problem is in your for loop.

You're using and iterator on block that is a list of lists. Then, by doing x.val you are trying to access the val attribute of lists, attribute that does not exist.

Try iterating one more time on x like for y in x.

answered Jul 17, 2019 at 9:01

Elbattore

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Louis Saglio · Accepted Answer · 2019-07-17 08:55:45Z

2

You forgot a nested for:

for x in block:
    for y in x:
        print(y.val)

answered Jul 17, 2019 at 8:55

Louis Saglio

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