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Sorting a list with mixed types
🐛 Fix the bug Topic: sorting Difficulty: medium Free
What this problem practises
The two sorting APIs are not interchangeable: sorted() returns a brand-new list while list.sort() sorts in place and returns None. Key functions compare the values they extract, and comparing mixed types raises TypeError.
This is a fix-the-bug problem: a short program is given in its broken state, and the task is to repair the code so it produces the required output. The interactive editor runs your fixed version in the browser and checks it for you — no setup, no local interpreter.
Difficulty: medium — expect to hold two interacting rules in your head at once, such as a boundary combined with a mutation.
The challenge
This should sort a list of scores, but it crashes because of one bad entry. Fix it.
The code runs in PyDebug’s in-browser compiler. Open the problem, run the snippet, watch the exact error or output, and keep iterating until it is right. Signed-in solves count toward XP and your daily streak.
The error it raises
Run the broken snippet and Python stops with this exact error: TypeError: '<' not supported between instances of 'str' and 'int'. Match it to the Python errors guide, then repair the line that produced it — knowing the message is half the fix.
The snippet
The interactive editor pre-fills exactly this code, broken and ready to repair:
scores = [88, 92, "75", 60]
sorted_scores = sorted(scores)
print(sorted_scores)More sorting problems
Keep going
- Python debugging guide — a systematic method for finding bugs like this one fast.
- Browse every sorting problem in this topic.
- Common Python errors and what they actually mean, plus the Python glossary for any term used on this page.