Balance checking in Blockchain / Solidity - Mini Project: Build & Apply

Balance checking

📖 Scenario: You are building a simple blockchain wallet app. Users have balances stored in a dictionary. You want to check how much balance each user has.

🎯 Goal: Create a program that stores user balances, sets a minimum balance threshold, finds users with balances above that threshold, and prints their names and balances.

📋 What You'll Learn

Create a dictionary called balances with exact user names and balances

Create a variable called min_balance with the exact value 100

Use a dictionary comprehension called rich_users to select users with balances greater than min_balance

Print the rich_users dictionary exactly as shown

💡 Why This Matters

🌍 Real World

Blockchain wallets need to check user balances to show available funds or to decide if a user can make a transaction.

💼 Career

Understanding how to filter and display balances is important for blockchain developers working on wallet apps or financial dashboards.

1

DATA SETUP: Create the user balances dictionary

Create a dictionary called balances with these exact entries: 'Alice': 150, 'Bob': 90, 'Charlie': 120, 'Diana': 80

Blockchain / Solidity

# Create the balances dictionary with exact user balances
# Your code here

Need a hint?

Use curly braces to create a dictionary with keys as user names and values as their balances.

2

CONFIGURATION: Set the minimum balance threshold

Create a variable called min_balance and set it to the integer 100

Blockchain / Solidity

balances = {'Alice': 150, 'Bob': 90, 'Charlie': 120, 'Diana': 80}
# Set the minimum balance threshold
# Your code here

Need a hint?

Just assign the number 100 to the variable min_balance.

3

CORE LOGIC: Select users with balances above the threshold

Use a dictionary comprehension called rich_users to select users from balances whose balance is greater than min_balance

Blockchain / Solidity

balances = {'Alice': 150, 'Bob': 90, 'Charlie': 120, 'Diana': 80}
min_balance = 100
# Create rich_users dictionary with users having balance > min_balance
# Your code here

Need a hint?

Use a dictionary comprehension with for user, bal in balances.items() and an if condition.

4

OUTPUT: Print the rich users dictionary

Write a print statement to display the rich_users dictionary

Blockchain / Solidity

balances = {'Alice': 150, 'Bob': 90, 'Charlie': 120, 'Diana': 80}
min_balance = 100
rich_users = {user: bal for user, bal in balances.items() if bal > min_balance}
# Print the rich_users dictionary
# Your code here

Need a hint?

Use print(rich_users) to show the dictionary.