On 1/27/2010 12:32 PM, Antoine Pitrou wrote:
Le Wed, 27 Jan 2010 02:20:53 -0800, Floris Bruynooghe a écrit :
Is a list or tuple better or more efficient in these situations?
Tuples are faster to allocate (they are allocated in one single step) and
quite a bit smaller too.
In some situations, in Python 2.7 and 3.1, they can also be ignored by
the garbage collector, yielding faster collections.
(not to mention that they are hashable, which can be useful)
Constant tuples (a tuple whose members are all seen as constants by the
compiler) are now pre-compiled and constructed once and put into the
code object as such rather than re-constructed with each run of the code.
>>> from dis import dis
>>> def l(): return [1,2,3]
>>> def t(): return 1,2,3
>>> dis(l)
1 0 LOAD_CONST 1 (1)
3 LOAD_CONST 2 (2)
6 LOAD_CONST 3 (3)
9 BUILD_LIST 3
12 RETURN_VALUE
>>> dis(t)
1 0 LOAD_CONST 4 ((1, 2, 3))
3 RETURN_VALUE
>>> # 3.1
Terry Jan Reedy
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