Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the scope and closure bugs pattern
Every callback reports the last value, a counter never increments, UnboundLocalError on a variable you can see.
What went wrong: each lambda uses the variable f, not the value f had when it was made. They all run after the loop, when f is 4.
The fix: [lambda x, f=f: x * f for f in factors]
Remember: functions made in a loop see the loop variable's last value unless you save it.
The pattern behind it: scope and closure bugs.
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<iframe src="https://trybughunt.com/embed/3078b247-6104-485b-b54b-19b9119317cb" title="Debugging challenge: All multipliers use the last number" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/3078b247-6104-485b-b54b-19b9119317cb">TryBugHunt</a></p>