type() and isinstance() in Python - Mini Project: Build & Apply

Check Data Types with type() and isinstance()

📖 Scenario: You are working on a simple program that needs to check the types of different pieces of data. This is like sorting your mail into letters, packages, and magazines before delivering them.

🎯 Goal: You will create a list of mixed data types, set a variable to check for a specific type, use type() and isinstance() to find which items match that type, and finally print the results.

📋 What You'll Learn

Create a list called items with mixed data types: 42, 3.14, 'hello', [1, 2, 3], and {'key': 'value'}.

Create a variable called check_type and set it to int.

Use a for loop with variables index and item to iterate over items with enumerate().

Inside the loop, use type() to check if item is exactly the check_type and print the index and item if true.

Also inside the loop, use isinstance() to check if item is an instance of check_type and print the index and item if true.

Print the results exactly as shown.

💡 Why This Matters

🌍 Real World

Checking data types is important when you receive mixed data, like user input or data from files, to make sure your program handles each piece correctly.

💼 Career

Many programming jobs require validating data types to avoid errors and to process data properly, especially in data science, web development, and software engineering.

1

Create a list of mixed data types

Create a list called items with these exact values in order: 42, 3.14, 'hello', [1, 2, 3], and {'key': 'value'}.

Python

# Create the list called items with the given values
# Your code here

Need a hint?

Use square brackets [] to create a list and separate items with commas.

2

Set the type to check

Create a variable called check_type and set it to the type int.

Python

items = [42, 3.14, 'hello', [1, 2, 3], {'key': 'value'}]
# Set check_type to int
# Your code here

Need a hint?

Use the keyword int without quotes to refer to the integer type.

3

Use a for loop with enumerate to check types

Use a for loop with variables index and item to iterate over items using enumerate(). Inside the loop, use type(item) == check_type to check if the item is exactly the type int. If true, print "type() match at index {index}: {item}". Also, use isinstance(item, check_type) to check if the item is an instance of int. If true, print "isinstance() match at index {index}: {item}".

Python

items = [42, 3.14, 'hello', [1, 2, 3], {'key': 'value'}]
check_type = int

# Loop over items with index and item
# Check type() and isinstance() inside the loop
# Your code here

Need a hint?

Use enumerate(items) to get both index and item in the loop.

Use f-strings to format the print output.

4

Print the final output

Run the program to print all matches found by type() and isinstance() checks. The output should show which items in items are integers.

Python

items = [42, 3.14, 'hello', [1, 2, 3], {'key': 'value'}]
check_type = int

for index, item in enumerate(items):
    if type(item) == check_type:
        print(f"type() match at index {index}: {item}")
    if isinstance(item, check_type):
        print(f"isinstance() match at index {index}: {item}")

# Run the program to see the output

Need a hint?

Check the console output to see the matches printed.