After this lesson, you will be able to:

• Use any() to detect whether at least one condition is true.
• Use all() to require every condition to be true.
• Combine comprehensions, comparisons, and string cleanup to build meaningful checks.
• Explain and correctly handle any([]) == False and all([]) == True when empty input is possible.

When a decision depends on many values, avoid writing counters or long chains of or and and unnecessarily.

• any(values) is true if at least one input is truthy.
• all(values) is true if every input is truthy.

You can first turn data into booleans with a list comprehension. This lesson deliberately uses comprehensions you already know; generator expressions come later.

checks = [result == "ok" for result in results]

For an empty input, any([]) is False, but all([]) is True. This is useful mathematically, but a release workflow usually requires at least one check before reporting that all checks passed. Add an explicit non-empty requirement when the business rule calls for it.

1. Detect at least one problem

alerts = [False, True, False]
print(any(alerts))

Output:

True

One truthy element is enough.

2. Require every item to pass

latencies = [42, 90, 110]
within_limit = [value <= 120 for value in latencies]
print(all(within_limit))

Output:

True

Every comparison is true.

3. Handle empty input deliberately

print(any([]))
print(all([]))

Output:

False
True

If empty means “no checks were run,” you may need bool(checks) and all(checks) instead.

4. Make predicates match real input data

responses = [" PASS ", "pass", " FAIL "]
normalized = [value.strip().lower() for value in responses]
print(any([value == "fail" for value in normalized]))

Output:

True

Normalize before comparing so capitalization and spaces do not change the decision.

1. all([]) is True—it does not mean a real validation took place.
2. Comparing raw strings can misclassify values containing spaces or different capitalization.
3. any() means “at least one,” not “exactly one.”
4. Do not confuse not any(...) with not all(...)—they describe different situations.