> On Do, 2017-09-07 at 15:13 -0300, David Rodrigues wrote:
>> I understand that array_filter() should costs more than for/foreach
>> it is a function call that call another function for each item, while
>> for/foreach is a language constructor that works on a way totally
>> and its optimized for this kind of job.
> The main cost in that is that array_filter has to create a copy of the
> array. An alternative is using an FilterIterator or generator or such
> which would make this a pipeline step. (with iterators there are
> multiple function calls, while the function descriptor is cached,
> making them relatively cheap) I'd focus on improving those.
As far as I can tell from the source `array_filter` does not create a
copy of the array. It initializes a new array and then appends to it.
If we want to improve the performance of `array_filter` we need to
examine output of common compilers to see if they hoist the
have_callback check out of the loop; I suspect it may not given the
complexity of ZEND_HASH_FOREACH_KEY_VAL_IND.