On Sunday, May 3, 2015 at 1:47:04 AM UTC+5:30, Tim Chase wrote: > [dangit, had Control down when I hit <enter> and it sent prematurely] > > On 2015-05-02 13:02, vasudevram wrote: > > http://jugad2.blogspot.in/2015/05/can-python-data-structure-reference.html > > > > https://docs.python.org/2/reference/datamodel.html > > > > and saw this excerpt: > > > > [ CPython implementation detail: CPython currently uses a > > reference-counting scheme with (optional) delayed > > detection of cyclically linked garbage, which collects > > most objects as soon as they become unreachable, but is > > not guaranteed to collect garbage containing circular > > references. ] > > > > Not sure whether it is relevant to the topic at hand, > > since, on the one hand, it uses the words "cyclically > > linked", but on the other, it says "garbage collection". > > The gotcha happens in a case where you do something like this: > > lst = [] > lst.append(lst) # create a cycle > del lst > > This creates a cycle, then makes it unreachable, but the list is > still referenced by itself, so the reference count never drops to > zero (where it would get GC'd), and thus that item lingers around in > memory. > > If you know that you're creating such cyclical structures, it's best > to manually unlink them before freeing them: > > lst = [] > lst.append(lst) # create the cycle > lst[:] = [] # break the cycle > # or lst.remove(lst) # though this takes more care > del lst > > -tkc
Thanks for the reply. Will check that out. -- https://mail.python.org/mailman/listinfo/python-list
