On Thu, Mar 1, 2018 at 2:16 AM, Serhiy Storchaka <storch...@gmail.com> wrote: > 28.02.18 16:56, Chris Angelico пише: >>>>> >>>>> def g(): >>>>> for x in range(5): >>>>> y = f(x) >>>>> yield [y, y] >>>>> stuff = list(g) >>>> >>>> >>>> >>>> You're not the first to mention this, but I thought it basically >>>> equivalent to the "expand into a loop" form. Is it really beneficial >>>> to expand it, not just into a loop, but into a generator function that >>>> contains a loop? >>> >>> >>> >>> It is slightly faster (if the list is not too small). It doesn't leak a >>> temporary variable after loop. And in many cases you don't need a list, >>> an >>> iterator would work as well. In these cases it is easy to just drop >>> calling >>> list(). >> >> >> Doesn't leak a temporary? In Python 3, the list comp won't leak >> anything, but the function is itself a temporary variable with >> permanent scope. You're right about the generator being sufficient at >> times, but honestly, if we're going to say "maybe you don't need the >> same result", then all syntax questions go out the window :D > > > Explicit for loop leaks variables x and y after the loop. They can hold > references to large objects. The generator function itself doesn't hold > references to the proceeded data. >
Oh, gotcha. Yeah. Will add that as another example. ChrisA _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
