Tobias Weber <t...@gmx.net> writes:
> Hi,
> whenever I type an "object literal" I'm unsure what optimisation will do
> to it.
>
> def m(arg):
> if arg & set([1,2,3]):
> return 4
>
> Is the set created every time the method is called? What about a
> frozenset? Or tuple vs list? After how many calls per second does it pay
> to save it at the module level? Would anybody else find this ugly?
>
> Also I never profiled the regular expression cache...
the dis module can help you for these:
>>> import dis
>>> def m(arg):
... if arg & set([1,2,3]):
... return 4
...
>>> dis.dis(m)
2 0 LOAD_FAST 0 (arg)
3 LOAD_GLOBAL 0 (set)
6 LOAD_CONST 1 (1)
9 LOAD_CONST 2 (2)
12 LOAD_CONST 3 (3)
15 BUILD_LIST 3
18 CALL_FUNCTION 1
21 BINARY_AND
22 JUMP_IF_FALSE 5 (to 30)
25 POP_TOP
3 26 LOAD_CONST 4 (4)
29 RETURN_VALUE
>> 30 POP_TOP
31 LOAD_CONST 0 (None)
34 RETURN_VALUE
As you can see, the list literal is built every time the function code
is executed.
--
Arnaud
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