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Date: Sat, 14 Oct 2023 19:11:05 -0400
Message-ID: <DB728AC9-4C22-4DF7-9767-CE14B91659F0@benramsey.com>
References: <e3fda36d-e248-4c98-9c46-5c33e7398098@app.fastmail.com>
Cc: David Grudl <david@grudl.com>, Levi Morrison <internals@lists.php.net>
In-Reply-To: <e3fda36d-e248-4c98-9c46-5c33e7398098@app.fastmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Subject: Re: [PHP-DEV] Two new functions array_first() and array_last()
From: ben@benramsey.com (Ben Ramsey)

> On Oct 14, 2023, at 16:30, Nikita Popov <nikita.ppv@gmail.com> wrote:
>=20
> =EF=BB=BFOn Sat, Oct 14, 2023, at 20:00, David Grudl wrote:
>> PHP lacks two very basic functions for working with arrays:
>>=20
>> - array_first() returning the first element of an array (or null)
>> - array_last() returning the last element of the array (or null)
>>=20
>> While PHP has functions that return the first and last keys,
>> array_key_first() and array_key_last(), it does not have more useful
>> functions for values.
>>=20
>> a) What about reset() and end()?
>> Programmers "abuse" the reset() and end() functions for this purpose.
>> The problem is that these functions are used to move the internal
>> pointer in the array. Which is why they have a name that is
>> inappropriate when used in the sense of "return me the first element".
>>=20
>> Much worse, they shouldn't to be used to get first/last value, because
>> they have a side effect (i.e. moving the pointer).
>>=20
>> Further, in the absence of an element, they return the obsolete false
>> and not the currently expected null, which can be combined with the ??
>> operator. In this they differ from the similar functions
>> array_key_first() and array_key_last().
>>=20
>> b) What about $array[array_key_first($array)]?
>>=20
>> For such basic functions as returning the first and last item in an
>> array, there should be a function in the basic package, not a
>> workaround. Moreover, this requires having the array in a local
>> variable, since $this->getFoo()[array_key_first($this->getFoo())]
>> would be very inefficient and possibly incorrect.
>>=20
>> c) Two such functions were proposed and rejected during the
>> array_key_first/last RFC
>> (https://wiki.php.net/rfc/array_key_first_last)
>>=20
>> Yes, that was in 2018. At that time, functions like str_contains() or
>> str_starts_with() wouldn't have even come into existence, just because
>> there was an obscure way to do it without them. I believe we've moved
>> on since then. Today we know how useful it is to use simple,
>> easy-to-understand methods, both for programmers who write and read
>> the code.
>>=20
>> DG
>=20
> I'm in favor of adding these.
>=20
> To add to what you already said, because reset/end modify the array, there=
's a good chance that calling these functions will copy the whole array due t=
o a modification you are not actually interested in.
>=20
> So basically you have the choice between calling end(), which is the wrong=
 thing to do semantically and may be slow, or using $array[array_key_last($a=
rray)], which is rather convoluted, and incorrect if the array is potentiall=
y empty.
>=20
> Regards,
> Nikita

I=E2=80=99m in favor of these functions, for all the same aforementioned rea=
sons.

Cheers,
Ben