Maciej Gol <maciej....@curo.ch> added the comment: This is a HUGE eye opener! Didn't know of that 'import' vs 'from x import y' difference. Thanks a lot! Is it documented somewhere ?
pt., 24 sty 2020, 15:08 użytkownik Serhiy Storchaka <rep...@bugs.python.org> napisał: > > Serhiy Storchaka <storchaka+cpyt...@gmail.com> added the comment: > > It is intended to support circular imports. Let foo.py contains "import > bar" and bar.py contains "import foo". When you execute "import foo", the > import machinery first creates an empty module foo, adds it to sys.modules, > reads foo.py and executes it in the namespace of module foo. When the > interpreter encounters "import bar" in foo.py, the import machinery creates > an empty module bar, adds it to sys.modules, reads bar.py and executes it > in the namespace of module bar. When the interpreter encounters "import > foo" in bar.py, the import machinery takes the module foo from sys.modules. > So you break an infinite cycle and can import modules with cyclic > dependencies. > > You can argue that cyclic import does not look as a good practice, but > actually it is pretty common case when you import a submodule in a package. > If foo/__init__.py contains "from .bar import Bar", the foo module must be > imported before you import foo.bar, but is not completely initialized at > that time yet. > > ---------- > > _______________________________________ > Python tracker <rep...@bugs.python.org> > <https://bugs.python.org/issue39430> > _______________________________________ > ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue39430> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
