FAQ: Build your own Mini-Blockchain! - Adding Blocks to the Blockchain


This community-built FAQ covers the “Adding Blocks to the Blockchain” exercise from the lesson “Build your own Mini-Blockchain!”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Introduction to Blockchain

FAQs on the exercise Adding Blocks to the Blockchain

There are currently no frequently asked questions associated with this exercise – that’s where you come in! You can contribute to this section by offering your own questions, answers, or clarifications on this exercise. Ask or answer a question by clicking reply (reply) below.

If you’ve had an “aha” moment about the concepts, formatting, syntax, or anything else with this exercise, consider sharing those insights! Teaching others and answering their questions is one of the best ways to learn and stay sharp.

Join the Discussion. Help a fellow learner on their journey.

Ask or answer a question about this exercise by clicking reply (reply) below!

Agree with a comment or answer? Like (like) to up-vote the contribution!

Need broader help or resources? Head here.

Looking for motivation to keep learning? Join our wider discussions.

Learn more about how to use this guide.

Found a bug? Report it!

Have a question about your account or billing? Reach out to our customer support team!

None of the above? Find out where to ask other questions here!

In the following code to add a new block:

def add_block(self, transactions):

firstly, where does the “transactions” come from and secondly, why aren’t we using self.transactions in the second line?

Up until this point we’ve been using sha256(string1.encode()) to hash something.

I don’t understand why we suddenly switch to .hash() and what it does.

chain is a list of dictionaries. The .hash is to call the value associated with the hash key in the dictionary located at len(self.chain)-1 in the list chain. The .hash is not acting as a method or function, simply as a dictionary key. Hopefully that helps.