Python Assert Statement

Python assert statement

Created By: chatGPT

The assert statement in Python is used for debugging purposes. It tests a condition, and if the condition evaluates to False, it raises an AssertionError. You can also provide an optional message to clarify the reason for the error. Using assert helps to identify errors in the code more easily during development.

assert condition, "Error message if the condition is False"

Here's a simple example to demonstrate how assert works. In this example, we check if a variable is equal to a certain value. If it is not, the assert statement will raise an error.

value = 10
assert value == 10, "Value should be 10"

# This will pass
assert value < 20, "Value should be less than 20"

# This will fail
assert value > 15, "Value should be greater than 15"

When you run the previous code, the first two assert statements will pass without any issue, but the third one will raise an AssertionError because the condition is False. The error message specified in the assert statement will also be displayed.

ValueError: Value should be greater than 15

Assertions can be globally disabled with the -O (optimize) switch when running Python, which means that in production code, you might want to avoid using asserts for essential checks, as they could be skipped. Instead, for critical checks that must always happen, use explicit conditions and raise exceptions.

if not condition:
    raise ValueError("This is a critical error message")