[Mike Coleman]
>> ... Regarding interning, I thought this only worked with strings.
Implementation details. Recent versions of CPython also, e.g.,
"intern" the empty tuple, and very small integers.
>> Is there some way to intern integers? I'm probably creating 300M
>> integers more or less uniformly distributed across range(10000)?
Interning would /vastly/ reduce memory use for ints in that case, from
gigabytes down to less than half a megabyte.
[Scott David Daniels]
> held = list(range(10000))
> ...
> troublesome_dict[string] = held[number_to_hold]
> ...
More generally, but a bit slower, for objects usable as dict keys,
change code of the form:
x = whatever_you_do_to_get_a_new_object()
use(x)
to:
x = whatever_you_do_to_get_a_new_object()
x = intern_it(x, x)
use(x)
where `intern_it` is defined like so once at the start of the program:
intern_it = {}.setdefault
This snippet may make the mechanism clearer:
>>> intern_it = {}.setdefault
>>> x = 3000
>>> id(intern_it(x, x))
36166156
>>> x = 1000 + 2000
>>> id(intern_it(x, x))
36166156
>>> x = "works for computed strings too"
>>> id(intern_it(x, x))
27062696
>>> x = "works for computed strings t" + "o" * 2
>>> id(intern_it(x, x))
27062696
_______________________________________________
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
