Lesson 11 of 19
Errors & Exceptions
Handle invalid input without crashing a program.
Introduction
Exceptions represent problems during execution, such as converting invalid text to a number.
Use try and except around code that may fail, and give users a useful fallback message.
Key insight
Handle invalid input without crashing a program.
Example
try:
age = int("twenty")
except ValueError:
print("Please enter a number")This example shows the core errors & exceptions idea in a small, runnable program.
Real-world example
Errors & Exceptions appears in everyday application code, scripts and APIs.
Test yourself
2-question check
1
What is the main idea in Errors & Exceptions?
2
Where can errors & exceptions be useful?
Ready to check your understanding?
Answer every question, then submit your quiz.
Try it yourself
Python compiler
Runs in your browser. Nothing is sent to a server.
Output appears here
First run downloads the Python runtime, so it may take a moment.
Practice challenge
Safely convert a user-entered value to a float.