[RFC] [Discussion] array_first() and array_last()

Hi Niels, It is reasonable. I have a userland implementation of that in my codebase since long ago. You missed the following point when discussing the behaviour for empty array: * Consistent with `array_shift()` and `array_pop()`, which are also about retrieving the first, respectively the last element of an array. —Claude

On 2025-04-05 18:51, Niels Dossche wrote:

Hi, Do you think it would be hard or wrong to add `array_nth`? I've had more trouble with that as the in-place implementation is usually pretty unreadable, e.g. array_slice(array_values($array), $offset, 1)[0] ?? null I understand this need is less common, especially compared to `array_first`. But I also suspect that an in-engine implementation might have more performance gains compared to an userland one. BR, Juris

On 4/5/2025 6:51 PM, Niels Dossche wrote:

-1 because returning `null` for empty arrays is still wrong. Whatever similar behavior exists should be corrected to throw `ValueError` in the future. Just my 2c.

On Sat, Apr 5, 2025 at 9:51 AM Niels Dossche <dossche.niels@gmail.com> wrote:

I dislike all the functions where `null` is a valid value, which can also be confused with an error in the operation. However, this is kind of in the grey area for me, because we do have plenty of tools to avoid the error condition. Of course there's the simple if: if (!empty($array) { $first = array_first($array); } And if we have a default value that could be used: $first = !empty($array) ? array_first($array) : $default; I would prefer a better design tool than returning null, but being honest, neither of these are too bad. As long as our documentation for these functions are helpful but concise about showing how to work around these edges, then I may be convinced to vote yes despite the design.

Hi, I think that this argument is not convincing, and even counterproductive: * NULL is a rare legitimate value, so the potential for clashing is low First, it says that it is a “rare” legitimate value, which one can disagree with. (I do disagree.) Second, the way it is formulated, it implies that, when `null` is used in array, there will be “clashing”, which is not necessarily the case. (I consider that there is almost never a clash, because it is rarely useful to make the difference between an explicit `null` and a missing value, and, when it is useful, you have almost surely already checked for an empty array upfront.) I suggest to replace that argument with the two following ones, that doesn’t treat arrays with NULL as second class citizens: * Semantically, NULL represents a missing value. Returning NULL from an empty array is not semantically incorrect, but it means that the function doesn’t differentiate between a implicit missing value (empty array) and an explicit missing value (array with NULL as its first/last element). * In the relatively rare cases you do want to make the difference between an empty array and an array that starts/ends with NULL, you can (and should) just check for empty array upfront. ------- One more thing. On https://www.php.net/, I read: “Fast, flexible and pragmatic, PHP powers everything from your blog to the most popular websites in the world.” (emphasis added). If we were to design some new perfect language, we might consider making `array_first()` (or equivalent) choke on empty arrays. But given the current state of the affairs, the pragmatic thing to do is to pave the cowpath. —Claude

On Sat, Apr 5, 2025, at 10:51 AM, Niels Dossche wrote:

To add another argument: the reset() workaround doesn't work with a readonly array property, because it does modify the array's internal pointer. https://3v4l.org/Zo5dZ Yes, I have in fact run into this situation in real code, which led me to use the $a[array_key_first($a)] dance instead. I'd love to replace it with a single call. --Larry Garfield

On 05/04/2025 17:51, Niels Dossche wrote:

Hi I'll be putting this to vote on Tuesday 22nd if no one has complaints. Kind regards Niels