assert — Easy Examples

Debugging aid that tests a condition and raises AssertionError if false

EasyIntermediateAdvancedExpert

Basic assertions

Using assert to verify conditions during development.

python
x = 10
assert x > 0, "x must be positive"
print("x is valid")

# Assert with expressions
name = "Alice"
assert len(name) > 0, "Name cannot be empty"
print(f"Name: {name}")

# Catching assertion errors
try:
    temperature = -300
    assert temperature > -273.15, f"Temperature {temperature} is below absolute zero"
except AssertionError as e:
    print(f"Invalid: {e}")
Expected Output
x is valid
Name: Alice
Invalid: Temperature -300 is below absolute zero

assert checks a condition and raises AssertionError if it's False. The message after the comma is optional but recommended.

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