Hi
On 2/1/23 18:21, Sergii Shymko wrote:
For example:
$originalList = ['first', '', 'last'];
$filteredList = array_filter($originalList);
var_export(filteredList); // array(0 => 'first', 2 => 'last')
var_export(array_is_list($originalList)); // true
var_export(array_is_list($filteredList)); // false
The behavior is counterintuitive and can lead to subtle bugs, such as encoding
issues:
echo json_encode($originalList); // ["first", "", "last"]
echo json_encode($filteredList); // {"0": "first", "2": "last"}
The workaround is to post-process the filtered array with array_values() to
reset the indexes.
The proposal is to introduce a function array_filter_list() that would work
solely on lists.
It will have the same signature as array_filter() and will always return a
valid list.
I agree with the general premise that "array_filter turns lists into
non-lists" is not great and I've encountered the issue myself more than
I would like. However I also agree with the other replies that
array_filter_list() is likely not the correct solution.
I believe that defaults matter and as a developer when I have the choice
between 'array_filter' and 'array_filter_list', the former is likely
going to be the default, because it's shorter. So instead of remembering
to wrap the array_filter() into array_values(), I have to remember which
of the two functions I need.
I also believe that non-array iterables should not be a second class
citizen to arrays and would like to point to my email in this mailing
list thread for the "[List/Assoc\unique]" RFC and thus a pretty similar
topic, because it also applies here:
https://externals.io/message/119070#119072
Perhaps the hypothetical "iterable\filter" function could be smart with
regard to the handling of keys? If the input appears to be consecutively
indexed, it is treated as a list and reindexed. Or it could default to
dropping the keys, which I consider the better default, because dropping
keys is *immediately* obvious when testing, whereas having holes in a
list is not.
Best regards
Tim Düsterhus
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