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Date: Fri, 7 Feb 2014 08:26:11 +0800
Message-ID: <CAHMUw2Eq6Zy1xCV9=-AaqWuSext2u5urf+wT1Rui13A71WQ_Zw@mail.gmail.com>
To: Chris Wright <daverandom@php.net>
Cc: "Kingsquare.nl - Robin Speekenbrink" <robin@kingsquare.nl>, PHP Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a1133ec96725c9104f1c60956
Subject: Re: [PHP-DEV] [discussion] add array_usearch()
From: tjerk.meesters@gmail.com (Tjerk Meesters)

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Hi Chris,


On Fri, Feb 7, 2014 at 4:28 AM, Chris Wright <daverandom@php.net> wrote:

> On 6 February 2014 19:55, Tjerk Meesters <tjerk.meesters@gmail.com> wrote:
> > Consider the following examples for finding a value in an array:
> >
> > array_search($value, $array, true);
> >
> > current(array_keys($array, $value, true));
> >
> > key(array_filter($array, function($item) use ($value) {
> >     return $item === $value;
> > }));
> >
> > Perhaps I've overlooked one way, but that's already three ways of doing
> > something similar; the difference lies in the memory behaviour, the first
> > being O(1) whereas the other two are O(n).
>
> I'm not sure where you got this statement from. array_search() is
> still O(n) in the worst case (when the needle is not found), which is
> the best you can hope for with such an operation. It's true that the
> other two are *always* O(n) whereas array_search() *could* return
> sooner than a complete iteration if the needle is found before the
> last element.
>

I was talking about memory growth, not runtime :)


>
> My initial reaction to this is one of "ye gods, not another array_*
> function", but I wouldn't be against altering the existing
> array_search() so that the third parameter is a bitmask of flags, one
> of which could indicate that the search should be case insensitive.
> This could be done in a BC-compliant manner if the flag that indicates
> strict comparisons has a value of 1.
>

I'm not wildly enthusiastic about another magic flags parameter, but it's
an acceptable compromise for me. The slight advantage there is that
`in_array()` would be bestowed upon the ability to take a callback function
as well. Something like:

if (in_array('is_numeric', $array, SEARCH_NEEDLE_IS_CALLBACK)) { ... }




>
> Thanks, Chris
>
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>


-- 
--
Tjerk

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