You really should also do a bit of work to make it easy for people to help
you. I just spent 5 minutes decyphering your text file so I could
reproduce your problem using this script:
<?
$array1 = array( array("aus_name"=>"Videografik", "aus_id"=>"1"),
array("aus_name"=>"Webdesign", "aus_id"=>"2"),
array("aus_name"=>"gfg fd", "aus_id"=>"3"),
array("aus_name"=>"df fds dfsdf", "aus_id"=>"4"),
array("aus_name"=>"fdf'' dfd fds","aus_id"=>"5"));
$array2 = array( array("aus_name"=>"Webdesign", "aus_id"=>"2"),
array("aus_name"=>"Videografik", "aus_id"=>"1"));
$n=0;
foreach ($array2 as $diff) {
$diff[$n]=array_diff($array1[$n], $array2[$n]);
$all[] = array ("aus_name" => $diff[$n][aus_name], "aus_id" => $diff[$n][aus_id]);
$n++;
}
var_dump ($all);
?>
This is 5 minutes I normally wouldn't have spent and would just have
skipped over your question because there was too much work for me.
So, looking at this code, let's manually look at what happens in that
foreach() loop of yours. You end up comparing the first element in array1
with the first element of array2 and on the second iteration you compare
the second element of array1 with the second element of array2. Like
this:
array("aus_name"=>"Videografik", "aus_id"=>"1") vs.
array("aus_name"=>"Webdesign", "aus_id"=>"2")
and
array("aus_name"=>"Webdesign", "aus_id"=>"2") vs.
array("aus_name"=>"Videografik", "aus_id"=>"1")
Now, the documentation for array_diff() states:
array_diff() returns an array containing all the values of array1 that
are not present in any of the other arguments. Note that keys are
preserved.
So, by looking at what you are comparing, and keeping what the
array_diff() function is documented to do in mind, we would expect an
output of:
array("aus_name"=>"Videografik", "aus_id"=>"1") the first time through
the loop as neither "Videografik" nor "1" appears in the second array
which consists of array("aus_name"=>"Webdesign", "aus_id"=>"2") and the
same goes for the second iteration.
So, the output you are getting is exactly what you coded.
Your main mistake:
You forgot that PHP arrays are ordered. That is, the order by which
elements are inserted is the order in which they appear when you loop
through them with foreach. This resulted in you not comparing
equivalent aus_id elements with each other.
You also don't seem to handle the difference in the number of elements
anywhere. If both sets starts with aus_id at 1 and go up from there, it
is clear that if array1 has 5 elements and array2 only has 2, then aus_id
3, 4 and 5 from array1 are the different without even checking. You
probably did realize this, and that is why you are doing the foreach()
over array2, but nowhere do you put these last 3 elements into your
difference array.
I think the easiest way to handle this is to rethink your problem.
Assuming you won't always have incrementing aus_id's the way you do and
you don't know whether array1 or array2 will have more elements, I would
suggest making a temp array keyed on the aus_id sorted correctly. Not
very hard to do, just do this:
foreach($array1 as $elem) $ar1[$elem['aus_id']] = $elem['aus_name'];
foreach($array2 as $elem) $ar2[$elem['aus_id']] = $elem['aus_name'];
ksort($ar1); ksort($ar2);
Now, the real benefit of this approach is that you just need to call
array_diff() once to get the diff you want. So here is the rewritten test
script:
$array1 = array( array("aus_name"=>"Videografik", "aus_id"=>"1"),
array("aus_name"=>"Webdesign", "aus_id"=>"2"),
array("aus_name"=>"gfg fd", "aus_id"=>"3"),
array("aus_name"=>"df fds dfsdf", "aus_id"=>"4"),
array("aus_name"=>"fdf'' dfd fds","aus_id"=>"5"));
$array2 = array( array("aus_name"=>"Webdesign", "aus_id"=>"2"),
array("aus_name"=>"Videografik", "aus_id"=>"1"));
foreach($array1 as $elem) $ar1[$elem['aus_id']] = $elem['aus_name'];
foreach($array2 as $elem) $ar2[$elem['aus_id']] = $elem['aus_name'];
ksort($ar1); ksort($ar2);
$diff = array_diff($ar1,$ar2);
var_dump($diff);
It's shorter, faster and it works.
-Rasmus
On Mon, 12 Aug 2002, Gandalf wrote:
> Win2k Pro and the latest PHP Version
>
> At 21:17 11.08.2002 -0700, you wrote:
> >First of all, which OS and PHP version?
> >
> >On Mon, 12 Aug 2002, Gandalf wrote:
> >
> > >
> > >
> > > Hello!
> > >
> > > First of all, i am trying to solve this problem for more then a week now, i
> > > looked through php.net for hours and have posted on numerous boards but
> > > nobody could come up and tell me what is going wrong.
> > >
> > > Basically, i have two multidimensional arrays, and i want to compare those
> > > two using array_diff().
> > >
> > > The problem is, that the output given is ecxactly the opposite of what
> > i want.
> > >
> > > To make it easier for those willing to help, i placed the sample code in a
> > > textfile so you can view it there.
> > >
> > > http://www.thebounceroom.com/problem.txt
> > >
> > > PLEASE, if you have some spare time have a look and tell me why this is not
> > > working as it should, as by now i am really frustrated, ive lost a
> > whole week
> > > by now and everybody else has to wait just because of me.
> > >
> > > Thanks a lot in advance for your time reading this!
> > >
> > > With best regards from Vienna,
> > > Jürgen
> > >
> > >
> > >
> > >
> > >
> > > --
> > > PHP General Mailing List (http://www.php.net/)
> > > To unsubscribe, visit: http://www.php.net/unsub.php
> > >
> >
> >
> >--
> >PHP General Mailing List (http://www.php.net/)
> >To unsubscribe, visit: http://www.php.net/unsub.php
>
> Jürgen (aka. Frodo the scribe
> ======================
> Visit the MECCG Forums at
> http://www.coen.at.tf
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