Why standards enable interoperability in Blockchain / Solidity - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a standard message format for blockchain transactions.

Blockchain / Solidity

transaction = {"sender": "Alice", "receiver": "Bob", "amount": 10, "currency": [1]

Drag options to blanks, or click blank then click option'

Atransaction

B10

CTrue

D"BTC"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number instead of a string for currency

Using a boolean value

The currency field should be a string representing the token type, like "BTC" for Bitcoin.

2fill in blank

medium

Complete the code to check if a transaction follows the standard by verifying the presence of the 'sender' key.

Blockchain / Solidity

if [1] in transaction:

Drag options to blanks, or click blank then click option'

A"sender"

B"receiver"

C"amount"

D"currency"

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for 'receiver' instead of 'sender'

Checking for 'amount'

To verify the transaction standard, we check if the 'sender' key exists in the transaction dictionary.

3fill in blank

hard

Fix the error in the code that validates the transaction amount is positive.

Blockchain / Solidity

if transaction["amount"] [1] 0:

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A<

B==

C>

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' instead of '>'

Using '==' which only checks for zero

The amount should be greater than 0 to be valid.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps transaction IDs to their amounts only if the amount is greater than 5.

Blockchain / Solidity

filtered_transactions = {tx_id: transaction[[1]] for tx_id, transaction in transactions.items() if transaction[[2]] > 5}

Drag options to blanks, or click blank then click option'

A"amount"

B"sender"

D"currency"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sender' or 'currency' instead of 'amount'

We use 'amount' as the key to get the transaction amount for both mapping and filtering.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase sender names to their transaction amounts if the currency is 'ETH'.

Blockchain / Solidity

eth_transactions = { [1]: [2] for tx_id, transaction in transactions.items() if transaction[[3]] == "ETH" }

Drag options to blanks, or click blank then click option'

Atransaction["sender"].upper()

Btransaction["amount"]

C"currency"

Dtx_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using tx_id as key instead of sender

Filtering by amount instead of currency

The comprehension maps the sender's uppercase name to the amount, filtering only transactions with currency 'ETH'.