Re: Looking for NULL in arrays

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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.

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Thread

Looking for NULL in arrays Derek Turner <frderek@suremail.je> - 2015-10-25 16:05 +0000
  Re: Looking for NULL in arrays Derek Turner <frderek@suremail.je> - 2015-10-25 16:11 +0000
    Re: Looking for NULL in arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-10-25 19:07 +0100
  Re: Looking for NULL in arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-10-25 19:06 +0100
    Re: Looking for NULL in arrays Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2015-10-25 21:01 +0100
      Re: Looking for NULL in arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-10-25 21:58 +0100
  Re: Looking for NULL in arrays Jerry Stuckle <jstucklex@attglobal.net> - 2015-10-25 16:33 -0400
    Re: Looking for NULL in arrays Derek Turner <frderek@suremail.je> - 2015-10-26 09:42 +0000
      Re: Looking for NULL in arrays Jerry Stuckle <jstucklex@attglobal.net> - 2015-10-26 09:45 -0400
        Re: Looking for NULL in arrays Derek Turner <frderek@suremail.je> - 2015-10-26 13:57 +0000
          Re: Looking for NULL in arrays Erwin Moller <erwinmollerusenet@xs4all.nl> - 2015-10-26 17:41 +0100
          Re: Looking for NULL in arrays Jerry Stuckle <jstucklex@attglobal.net> - 2015-10-26 12:49 -0400
      Re: Looking for NULL in arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-10-26 22:25 +0100
  Re: Looking for NULL in arrays Denis McMahon <denismfmcmahon@gmail.com> - 2015-10-27 03:16 +0000
    Re: Looking for NULL in arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-10-27 22:23 +0100

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