Serhiy Storchaka <storchaka+cpyt...@gmail.com> added the comment:
> However, that's still going to be clearer to most readers than writing It is subjective. To me, j+1/j looks clearer than (j:=i*i)+1/j. In addition, the for-as-assignment idiom is more powerful in context of comprehensions, it allows to set an initial value. In any case I want to have a choice. > OOC, rather than optimizing a fairly ugly use case, might another approach be > to make walrus less leaky? I think this ship is sailed. The semantic of the walrus operator is complex enough to make it even more complex by adding more special cases. Also, while the function-wide optimization of variables is possible, it much more complex problem than the proposed simple optimization. > You should probably rerun your benchmarks though $ ./python -m timeit -s 'a = list(range(1000))' -- '[y for x in a for y in [x]]' Unpatched: 5000 loops, best of 5: 66.8 usec per loop Patched: 10000 loops, best of 5: 21.5 usec per loop $ ./python -m timeit -s 'a = list(range(1000))' -- '[x for x in a]' 20000 loops, best of 5: 17.8 usec per loop Issue32925 reduce the difference, but it is still large (~12). ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue32856> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
