访问区块链对象中的数据以获取钱包余额

Question

While trying to execute the code below to access the wallet balance in the blockchain, I'm getting the error:

TypeError: slice indices must be integers or None or have an index method

This is the code I use:

class Blockchain:

def __init__(self):
    self.chain = [] #stores the blockchain
    self.transactions = ["Plain as vanilla"]
    self.create_block(proof = 1, previous_hash="0") #helps with block creation
    self.nodes = set()
    

def create_block(self, proof, previous_hash):
    """ Used to make a block """
    block = {
        'index': len(self.chain) + 1,
        'timestamp': str(datetime.datetime.utcnow()),
        'proof': proof,
        'previous_hash': previous_hash,
        'data': self.transactions
    }
    self.transactions = []
    self.chain.append(block)
    return block        

self.balance = 0
chain = Blockchain.chain[]
i = 0
for x in range(len(chain)):
        if chain[i:"data":"reciver"] or chain[i:"data":"sender"] == publickey:
            io = 0
            for chain[i:"data":"reciver"] in chain[i:"data"]: #loop for iterating through the dictionary
                amount = int(chain[io:"data":"amount"])
                self.balance = self.balance + amount
                io = io + 1

        if chain[i:"data":"sender"] == publickey:
            amount = int(chain[i:"data":"amount"])
            self.balance = self.balance - amount
        
        i = i + 1
    if chain[-1] == 0:
        self.balance = 0
        return self.balance

the code is supposed to iterate through a dictionary inside a dictionary inside a list to find the balance of a wallet inside a blockchain, edit: I added the method of how a block is structured on the chain

Answer 1

Can you provide the error message? I see that you instantiate "chain" as an empty list and then loops over it.

But assuming that you're only showing that the variable exists, to access a dictionary, nested inside a second dictionary within this list you should use:

chain[i]["data"]["receiver"]