Type conversion (int, float, string) in Python - Mini Project: Build & Apply

Type conversion (int, float, string)

📖 Scenario: Imagine you are working in a small shop. You receive product prices as strings from the cashier's system, but you need to calculate totals and show prices properly formatted.

🎯 Goal: You will create variables with prices as strings, convert them to numbers to calculate totals, and then convert the result back to a string to display.

📋 What You'll Learn

Create variables with prices as strings

Create a variable to hold a discount rate as a float

Convert string prices to integers or floats for calculation

Calculate the total price after discount

Convert the total price back to a string for display

Print the final total price as a string

💡 Why This Matters

🌍 Real World

In shops or online stores, prices often come as text and need conversion to numbers for calculations like totals and discounts.

💼 Career

Understanding type conversion is essential for data processing, user input handling, and preparing data for calculations in many programming jobs.

1

Create price variables as strings

Create three variables called price1, price2, and price3 with the string values '100', '250.5', and '399' respectively.

Python

# Create three string variables price1, price2, price3 with values '100', '250.5', '399'
# Your code here

Need a hint?

Use quotes around numbers to make them strings, like price1 = '100'.

2

Create a discount rate as a float

Create a variable called discount_rate and set it to the float value 0.1 (which means 10%).

Python

price1 = '100'
price2 = '250.5'
price3 = '399'
# Create a float variable discount_rate with value 0.1
# Your code here

Need a hint?

Write discount_rate = 0.1 without quotes to make it a float.

3

Convert prices to numbers and calculate total

Convert price1 and price3 to integers using int(), convert price2 to a float using float(), then calculate the total price after applying the discount rate. Store the result in a variable called total_price.

Python

price1 = '100'
price2 = '250.5'
price3 = '399'
discount_rate = 0.1
# Convert prices to numbers and calculate total_price after discount
# Your code here

Need a hint?

Use int() for whole numbers and float() for decimal numbers. Then add and apply discount.

4

Convert total to string and print

Convert the total_price to a string using str() and print it with the message: Total price after discount: followed by the converted string.

Python

price1 = '100'
price2 = '250.5'
price3 = '399'
discount_rate = 0.1
price1_num = int(price1)
price2_num = float(price2)
price3_num = int(price3)
total_before_discount = price1_num + price2_num + price3_num
total_price = total_before_discount * (1 - discount_rate)
# Convert total_price to string and print with message
# Your code here

Need a hint?

Use str(total_price) to convert the number to text, then print with the message.