sorts/radix_sort.py: radix_sort() does not raise exception for negative inputs

[greemich-bot]

Repository commit

567bb93

Python version (python --version)

Python 3.14.2

Dependencies version (pip freeze)

contourpy==1.3.3
cycler==0.12.1
dnspython==2.8.0
fonttools==4.62.1
iniconfig==2.3.0
kiwisolver==1.5.0
matplotlib==3.10.8
numpy==2.4.4
packaging==26.0
pillow==12.2.0
pluggy==1.6.0
Pygments==2.20.0
pymongo==4.17.0
pyparsing==3.3.2
pytest==9.1.1
pytest-timeout==2.4.0
python-dateutil==2.9.0.post0
pyzmq==27.1.0
six==1.17.0

Expected behavior

radix_sort() should raise a value error when a negative value is used.

ex. radix_sort([1, 3, -2, 4]) should raise ValueError because a negative value will not map to the correct bucket.

Actual behavior

When provided a negative value, radix_sort() proceeds with sorting and returns an incorrectly sorted array.
Ex. radix_sort([1, 3, -2, 4]) returns [1, 3, 4, -2]

Place test_radix_sort.py in the same directory and run "pytest test_radix_sort.py" to replicate.

This is a small bug, but violates the definition that "Algorithms should: ... raise Python exceptions (ValueError, etc.) on erroneous input values."

Suggested action

Add a check when sorting the list_of_ints into buckets that raises a ValueError if i < 0. I am willing to implement this.

[sofia-80]

It looks like the radix_sort() function needs an explicit check for negative values before proceeding with the sorting logic. You could add a condition at the beginning of the function that raises a ValueError if any element in the input list is negative. This could be done using a simple if any(x < 0 for x in list_of_ints): statement. Additionally, it would be beneficial to update the documentation to inform users about this new constraint. Would you also consider adding a test case in test_radix_sort.py to ensure that this exception is raised when negative inputs are provided?