Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:61649
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.216.170 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <2075060250.98513.1343049996761.JavaMail.open-xchange@oxwebmail.registrar-servers.com>
References: <2075060250.98513.1343049996761.JavaMail.open-xchange@oxwebmail.registrar-servers.com>
Date: Mon, 23 Jul 2012 12:05:40 -0400
Message-ID: <CAAyV7nE6Of+SeDUGaJt2mNTT3RYJ4HdX_0PeL53x5doa6NWGow@mail.gmail.com>
To: Andrew Faulds <ajf@ajf.me>
Cc: internals@lists.php.net
Content-Type: multipart/alternative; boundary=00248c768f9ed348c204c5816adc
Subject: Re: [PHP-DEV] array_pick() - resent because email client broke formatting
From: ircmaxell@gmail.com (Anthony Ferrara)

--00248c768f9ed348c204c5816adc
Content-Type: text/plain; charset=ISO-8859-1

Andrew,

On Mon, Jul 23, 2012 at 9:26 AM, Andrew Faulds <ajf@ajf.me> wrote:

>
> (resending because of broken formatting)
>
> Hi there,
>
> I apologise for my previous email. It was a disorganised mess that didn't
> really
> make the case for that function very well. So here's a proper proposal
> (perhaps
> too proper?).
>
> Introduction ------------
>
> I am proposing a function, named array_pick(), which takes a single (array)
> argument, and returns a random value from it.
>
> Implementation --------------
>
> https://github.com/php/php-src/pull/142
>
> Specification -------------
>
> mixed array_pick(array $array);
> The function returns the value of one random array element from $array.
> Should
> said array be empty, then it should return NULL.
>
> Rationale ---------
>
> - array_rand exists, however it only gets a random key, not a random
> value. This
> is the logical counterpart for API completeness
> - array_pick is more convenient than $a[array_rand($a)], especially for
> these
> cases:
>   - short array syntax + array_pick, e.g. some_func(array_pick(['foo.png',
> 'bar.jpg', 'foobar.gif'])) vs $a = ['foo.png, 'bar.jpg', 'foobar.gif'];
> some_func($a[array_rand($a)]);
>   - where using long names or nested arrays, e.g.
> some_func(array_pick($foo['bar']['foobar']));
> - array_pick is less wasteful than shuffling an array and taking the first
> element
> - $a[array_rand($a)] issuse a NOTICE from an undefined index if the array
> is
> empty, but array_pick() just returns null, which is more convenient
> - I need this function myself quite often. It exists in two other
> languages I
> use that I can think of off the top of my head (Python, Game Maker
> Language)
>
> Objections ----------
> - PHP has too many functions
>   - Yes, but that doesn't mean we can't add more. Otherwise we can't
> improve
> things and move forward.
>

Broken Window Theory. http://en.wikipedia.org/wiki/Broken_windows_theory

Saying things are already broken is never a valid justification for
breaking things further.


> - This can be easily implemented in userland code/this is too frivolous to
> warrant addition
>   - This is true, however similarly to a lot of standard library
> functionality,
> it is used frequently enough that it is silly to have to rewrite it every
> time
> it is needed
>

It's a one-liner. It's not like it's non-trivial, or there are weird
edge-cases, or security implications. It's a one line implementation:

function array_pick(array $array) {
    return empty($array) ? null : $array[array_rand($array)];
}


>   - It is also the logical counterpart to array_rand(). One for a key, one
> for a
> value.
>

Again, since it's so trivial to implement, why is it needed? Symmetry is a
decent goal, but justified symmetry. Not just symmetry for the sake of it...


> - The name isn't logical
>   - Whilst you could argue that array_rand_key is a better name, I have
> chosen
> array_pick because it is shorter, and has a similar name to similar
> functions in
> Python (random.choice) and GML (choose)
>

Actually, I think that array_pick() is a poor name. Python's name makes
sense, because it's bound to the random namespace. But being bound to the
array namespace indicates a different thing. I would argue that
array_random_value() would be a better choice (or any one of a number of
names)...


> ---
> Thoughts?
>

Shared.

Thanks,

Anthony

--00248c768f9ed348c204c5816adc--