pythonLogic errorEasy

Set difference operator direction inverts unmatched items

Time: 0:00

BugFind the bug and fix the code

What it should do

find_missing_required_keys(provided_keys, required_keys) returns the missing required keys in sorted order. Example: find_missing_required_keys(["id"], ["id", "email"]) → ["email"].

What happens instead

find_missing_required_keys(["id", "extra"], ["id", "email"]) returns ["extra"] instead of ["email"].

def find_missing_required_keys(provided_keys, required_keys):
    return list(set(provided_keys) - set(required_keys))

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

⏱️0:00

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Take a moment to read the bug symptom and trace the code with Run & Check before unlocking Hint 1.

Hint 2

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Hint 3

Unlocks after Hint 2

This bug belongs to the logic errors pattern

The wrong operator, an inverted condition, a formula the right way round but backwards.

Learn the logic errors pattern Step through your own code

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pythonLogic errorEasy

Set difference operator direction inverts unmatched items

Time: 0:00

BugFind the bug and fix the code

What it should do

find_missing_required_keys(provided_keys, required_keys) returns the missing required keys in sorted order. Example: find_missing_required_keys(["id"], ["id", "email"]) → ["email"].

What happens instead

find_missing_required_keys(["id", "extra"], ["id", "email"]) returns ["extra"] instead of ["email"].

def find_missing_required_keys(provided_keys, required_keys):
    return list(set(provided_keys) - set(required_keys))

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

⏱️0:00

Hints

🏆 0 hints = Flawless Solve

Think & Test Cooldown

2:00 remaining

Take a moment to read the bug symptom and trace the code with Run & Check before unlocking Hint 1.

Hint 2

Unlocks after Hint 1

Hint 3

Unlocks after Hint 2

This bug belongs to the logic errors pattern

The wrong operator, an inverted condition, a formula the right way round but backwards.

Learn the logic errors pattern Step through your own code

Set difference operator direction inverts unmatched items

What it should do

What happens instead

More logic errors to practise

Related errors

Set difference operator direction inverts unmatched items

What it should do

What happens instead

More logic errors to practise

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