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Date: Thu, 23 Aug 2012 15:22:55 +0900
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To: Andrew Faulds <ajf@ajf.me>
Cc: Levi Morrison <morrison.levi@gmail.com>, Rasmus Schultz <rasmus@mindplay.dk>, internals@lists.php.net
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Subject: Re: [PHP-DEV] removing an item from an array
From: yohgaki@ohgaki.net (Yasuo Ohgaki)

Hi,

2012/8/22 Andrew Faulds <ajf@ajf.me>:
> Um, Yasuo, have you looked at array_walk implementation and ascertained it
> is safe to change array structure while using it?
>
> Because I'm worried you're changing docs without doing so.

Simply deleting current element is safe.
It's done in everywhere in PHP. It's just like deleting elements with
zend hash.

array_walk() could bite users.
If programmer sort or delete element to be processed next, it causes problem.
PHP programmer will not sort or delete next element to processed while working
with zend hash, but average PHP users do not care about internal.

I finally understand why people use array_filter() to delete elements and
I think we should have array_udelete() since the API is much safer than
array_walk().

Regards,

--
Yasuo Ohgaki
yohgaki@ohgaki.net

>
> --
> Sent from Samsung Mobile
> Andrew Faulds
> http://ajf.me/
>
>
>
> Yasuo Ohgaki <yohgaki@ohgaki.net> wrote:
>
>
> Hi,
>
> 2012/8/22 Levi Morrison <morrison.levi@gmail.com>:
>> On Tue, Aug 21, 2012 at 7:45 PM, Yasuo Ohgaki <yohgaki@ohgaki.net> wrote:
>>>
>>> Hi,
>>>
>>> 2012/8/16 Rasmus Schultz <rasmus@mindplay.dk>:
>>> > How come there is no straight-foward obvious way to simply remove a
>>> > given
>>> > value from an array?
>>> >
>>> > Just look at the number of horrible ways people solve this obvious
>>> > problem:
>>> >
>>> >
>>> > http://stackoverflow.com/questions/7225070/php-array-delete-by-value-not-key
>>> >
>>> > Shouldn't we have something simple, like:
>>> >
>>> >     array_remove($array, $value) : array (returns a new array)
>>> >
>>> > and/or
>>> >
>>> >     array_delete(&$array, $value) : bool (modifies array directly)
>>> >
>>> > ?
>>>
>>> It was amazing that this thread has close to 90 mails.
>>>
>>> I've added some use cases of array_udelete() to wiki, since
>>> some people fails to see how it could be useful. I also bring
>>> back to array_walk() version of equivalent example. I just
>>> don't see any reason why we should replace it with slower
>>> foreach() version.
>>>
>>> I think the RFC page is almost complete.
>>>
>>> https://wiki.php.net/rfc/array_delete
>>>
>>> Any more comments?
>>>
>>> --
>>> Yasuo Ohgaki
>>> yohgaki@ohgaki.net
>>
>> Take a look at:
>>
>> http://php.net/manual/en/function.array-walk.php#refsect1-function.array-walk-parameters
>>
>> Look at funcname parameter.  Notice:
>>> Only the values of the array may potentially be changed; its structure
>>> cannot be altered, i.e., the programmer cannot add, unset or reorder
>>> elements. If the callback does not respect this requirement, the behavior of
>>> this function is undefined, and unpredictable.
>>
>> I'm just going to change the behavior back when you switch it to
>> array_walk. It's less clear and technically undefined.
>
> Ok, then my commit to the doc was outstanding still.
> Old PHP was behaved badly with reference variables.
> I'll remove obsolete statement.
>
> I'll fix it later.
> Thank you.
>
> --
> Yasuo Ohgaki
> yohgaki@ohgaki.net
>
> --
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