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From: Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups: comp.lang.php
Subject: Re: Looking for NULL in arrays
Date: Tue, 27 Oct 2015 22:23:23 +0100
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Denis McMahon wrote:

> On Sun, 25 Oct 2015 16:05:19 +0000, Derek Turner wrote:
>> that will detect a NULL value and stop.
                      ^^^^^^^^^^ 
> Works with the test cases shown, but otherwise untested so no guarantees
> of any specific behaviour if you feed it garbage.
> 
> <?php
> 
> $a = array(
> array("fred","jim","peter","susan","mary",0),
> array("fred","jim","susan","mary",0),
> array("fred","susan","mary",0),
> array("fred","mary",0),
> array("fred",0),
> array("fred","jim","susan","mary",0,0),
> array("fred","susan","mary",0,0,0),
> array("fred","mary",0,0,0,0),
> array("fred",0,0,0,0,0)
> );

Flawed testcase: There is not a single occurrence of “null” or “NULL” there.
 
> foreach ($a as $arr) {
>   $idx = 0;
>   while ($idx < count($arr)-1 && $arr[$idx] != NULL) $idx += 1;

“!= null” is a comparison recommended against as it does type juggling.

In PHP, “null” (or “NULL”) is a special value.  It is *that value* that were 
to be detected.  And the requirement was to do this *without* “having to use 
an 'if' or similar test”, which your approach obviously does not meet.  (The 
reason for that is that it cannot be met.)

-- 
PointedEars
Zend Certified PHP Engineer
Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.