[someplaceguy]

    return l[len(l) / 2]

I'm not a Python expert, but doesn't the `/` operator return a float in Python? Why would you use a float as an array index instead of doing integer division (with `//`)?

I know this probably won't matter until you have extremely large arrays, but this is still quite a code smell.

Perhaps this could be forgiven if you're a Python novice and hadn't realized that the two different operators exist, but this is not the case here, as the article contains this even more baffling code which uses integer division in one branch but float division in the other:

    def quickselect_median(l, pivot_fn=random.choice):
        if len(l) % 2 == 1:
            return quickselect(l, len(l) // 2, pivot_fn)
        else:
            return 0.5 * (quickselect(l, len(l) / 2 - 1, pivot_fn) +
                           quickselect(l, len(l) / 2, pivot_fn))

That we're 50 comments in and nobody seems to have noticed this only serves to reinforce my existing prejudice against the average Python code quality.

[jononor]

Well spotted! In Python 2 there was only one operator, but in Python 3 they are distinct. Indexing an array with a float raises an exception, I believe.

[runeblaze]

I do agree that it is a code smell. However given that this is an algorithms article I don't think it is exactly that fair to judge it based on code quality. I think of it as: instead of writing it in pseudocode the author chose a real pseudocode-like programming language, and it (presumably) runs well for illustrative purposes.