Accounts (EOA vs contract accounts) in Blockchain / Solidity - Hands-On Comparison

Understanding Accounts: EOA vs Contract Accounts

📖 Scenario: Imagine you are learning about blockchain accounts. There are two main types: Externally Owned Accounts (EOA), which are controlled by people, and Contract Accounts, which are controlled by code (smart contracts).We will create a simple program to represent these accounts and check their types.

🎯 Goal: You will build a small program that stores a list of accounts with their types and then filters out only the EOAs.

📋 What You'll Learn

Create a dictionary called accounts with account addresses as keys and their types ('EOA' or 'Contract') as values.

Create a variable called filter_type and set it to the string 'EOA'.

Use a dictionary comprehension to create a new dictionary called eoa_accounts that contains only the accounts of type 'EOA'.

Print the eoa_accounts dictionary.

💡 Why This Matters

🌍 Real World

Blockchain developers often need to distinguish between EOAs and contract accounts to manage transactions and smart contract interactions correctly.

💼 Career

Understanding account types is essential for blockchain engineers, smart contract developers, and security analysts working with Ethereum or similar platforms.

1

Create the accounts dictionary

Create a dictionary called accounts with these exact entries: '0xabc123': 'EOA', '0xdef456': 'Contract', '0xghi789': 'EOA', '0xjkl012': 'Contract'.

Blockchain / Solidity

# Create the accounts dictionary with given addresses and types
# Your code here

Need a hint?

Use curly braces {} to create a dictionary with the exact keys and values.

2

Set the filter type

Create a variable called filter_type and set it to the string 'EOA'.

Blockchain / Solidity

accounts = {
    '0xabc123': 'EOA',
    '0xdef456': 'Contract',
    '0xghi789': 'EOA',
    '0xjkl012': 'Contract'
}
# Create filter_type variable set to 'EOA'
# Your code here

Need a hint?

Assign the string 'EOA' to the variable named filter_type.

3

Filter EOAs using dictionary comprehension

Use a dictionary comprehension to create a new dictionary called eoa_accounts that contains only the accounts from accounts where the value equals filter_type. Use for address, acc_type in accounts.items() in your comprehension.

Blockchain / Solidity

accounts = {
    '0xabc123': 'EOA',
    '0xdef456': 'Contract',
    '0xghi789': 'EOA',
    '0xjkl012': 'Contract'
}
filter_type = 'EOA'
# Create eoa_accounts dictionary with only EOAs using dictionary comprehension
# Your code here

Need a hint?

Use {key: value for key, value in dict.items() if condition} to filter the dictionary.

4

Print the filtered EOAs

Write print(eoa_accounts) to display the dictionary of EOAs.

Blockchain / Solidity

accounts = {
    '0xabc123': 'EOA',
    '0xdef456': 'Contract',
    '0xghi789': 'EOA',
    '0xjkl012': 'Contract'
}
filter_type = 'EOA'
eoa_accounts = {address: acc_type for address, acc_type in accounts.items() if acc_type == filter_type}
# Print the eoa_accounts dictionary
# Your code here

Need a hint?

Use the print function to show the eoa_accounts dictionary.