New submission from Tim Peters <t...@python.org>: This has come up repeatedly, and the docs should be updated to resolve it:
https://stackoverflow.com/questions/48603998/python-iterating-over-a-list-but-i-want-to-add-to-that-list-while-in-the-loop/48604036#48604036 Seemingly the only relevant documentation is in the reference manual, but it's flawed: https://docs.python.org/3.7/reference/compound_stmts.html#the-for-statement - The behavior it's describing is specific to list iterators, but it pretends to apply to "mutable sequences" in general (which may or may not mimic list iterators in relevant respects). - It's not clear that the "length of the sequence" (list!) is evaluated anew on each iteration (not, e.g., captured once at the start of the `for` loop). - While it describes things that can go wrong, it doesn't describe the common useful case: appending to a list during iteration (for example, in a breadth-first search). ---------- assignee: docs@python components: Documentation messages: 311614 nosy: docs@python, tim.peters priority: normal severity: normal stage: needs patch status: open title: Mutating a list while iterating: clarify the docs type: enhancement versions: Python 2.7, Python 3.4, Python 3.5, Python 3.6, Python 3.7, Python 3.8 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue32767> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
