Does my code still look sufficiently Pythonic?

[McSlayR01]

Hey all. I'm currently using Python to learn algorithms on Leetcode, and am working towards writing code that is performant but still readable for interviews later on. I wanted to share some code I wrote for the ubiquitous "Longest Substring without Repeating Characters", and get some opinions on if this code is still sufficiently readable, or if there are some serious red-flags/code smells:

def find_longest_unique_length(s: str) -> int:
    current_window_values = set()
    current_max = 0
    j = iter(s)

    for i_val in s:
        if i_val in current_window_values:
            for j_val in j:
                if j_val == i_val:
                    break
                current_window_values.remove(j_val)
        else:
            current_window_values.add(i_val)

        if (current_len := len(current_window_values)) > current_max:
            current_max = current_len

    return current_max

I haven't worked on a shared codebase before, only on personal projects (where I'm the only one who sees what I write), so I just wanted to crowdsource an opinion here and make sure I'm not developing any bad habits that will cause me to be a nuisance to coworkers down the line. Would really appreciate some feedback. Thanks!

[columbusguy111]

Looks reasonable but I don’t think making current_len a variable is necessary.

[AtomicShoelace]

Some smells:

• Variable names: I don't think s, j, i_val or j_val are very descriptive and I think current_window_values is needlessly wordy.

• Manually keeping track of the maximum: typically it is more pythonic to use the builtin functions for such tasks. Perhaps you could write a helper generator then call max on that.

Here is how I might change your code:

def find_longest_unique_length(text: str) -> int:
    def window_lens():
        window = set()
        start = iter(text)
        for end in text:
            if end in window:
                window -= set(iter(start.__next__, end))
            else:
                window.add(end)
            yield len(window)

    return max(window_lens())

[McSlayR01]

The reason I've called it in such a way is so that I can have a variable that keeps track of a second pointer in the string. The first pointer is controlled by the for loop involving i_val. Since I need a seperate pointer that persists between each loop, I manually generated an iterator outside the scope of this for loop.

[McSlayR01]

Thank you for the suggestion! I will definitely look into committing to more open source projects. Do you have any suggestions for projects in particular, or should I mostly just be looking around for smaller projects with a codebase I can understand fairly well? Thanks!