Tell me more ×
Stack Overflow is a question and answer site for professional and enthusiast programmers. It's 100% free, no registration required.
up vote 2 down vote favorite

Good evening (middle-european time).

Although my question could be a bit embarassing (because it may be sooo easy) I'm asking you. I apologize in advance but i've been coding for about 10 hours today and need to get this last thing done.

So, is there an array function - honestly i searched for about an hour - in php that somehow does array_merge, comparing the values, ignoring the keys. I think array_unique(array_merge($a, $b)); must be working, however I believe there is a nicer way to do this.

eg.

$a = array(0 => 0, 1 => 1, 2 => 2);
$b = array(0 => 2, 1 => 3, 2 => 4);

resulting in: 

$ab = array(0 => 0, 1 => 1, 2 => 2, 3 => 3, 4 => 4);

Please note that I don't care about the keys in $ab, however it would be nice if they were ascending, starting at 0 to count($ab)-1.

Thanks in advance.

share|improve this question
your solution is fine – mfonda Jan 11 '11 at 17:47
ok mfonda, thank you very much! – Valorized Jan 11 '11 at 17:49
1  
I don't think there is a nicer way to do this. array_unique(array_merge($a, $b)) is actually a pretty elegant solution. – Ben Lee Jan 11 '11 at 17:50
It is good to note that this will only work if the keys are numeric or guaranteed to be unique between the two arrays, otherwise array_merge will overwrite. – Will Jan 11 '11 at 17:52
Thanks Ben Lee. Now I can go to bed ;-) I just thought I got somehow... blind. Thanks to all. – Valorized Jan 11 '11 at 17:53

5 Answers

up vote 5 down vote accepted 
function umerge($arrays){
 $result = array();
 foreach($arrays as $array){
  $array = (array) $array;
  foreach($array as $value){
   if(array_search($value,$result)===false)$result[]=$value;
  }
 }
 return $result;
}
share|improve this answer
i will select this on as the correct answer, because it is a nice way to do it. However you wrote "reult" instead of result in line 5. Another way: array_merge(array_unique(array_merge($a, $b))); Thanks all. – Valorized Jan 11 '11 at 18:06
thanx I´ll edit it – Oliver A. Jan 11 '11 at 18:12
9  
Or... array_unique(array_merge($myArray,$myOtherArray)); – doublejosh Aug 10 '11 at 1:35
up vote 1 down vote

To answer the question as asked, for a general solution that also works with associative arrays while preserving keys, I believe that you will find this solution most satisfactory:

/**
 * array_merge_unique - return an array of unique values,
 * composed of merging one or more argument array(s).
 *
 * As with array_merge, later keys overwrite earlier keys.
 * Unlike array_merge, however, this rule applies equally to
 * numeric keys, but does not necessarily preserve the original
 * numeric keys.
 */
function array_merge_unique(array $array1 /* [, array $...] */) {
  $result = array_flip(array_flip($array1));
  foreach (array_slice(func_get_args(),1) as $arg) { 
    $result = 
      array_flip(
        array_flip(
          array_merge($result,$arg)));
  } 
  return $result;
}
share|improve this answer
up vote 0 down vote

array_merge will ignore numeric keys, so in your example array_merge($a, $b) would give you $ab, there is no need to call array_unique().

if you have string keys (i.e. an associative array) use array_values() first:

array_merge(array_values($a), array_values($b));
share|improve this answer
he wants the unique values though, so he needs to call array_unique – Will Jan 11 '11 at 17:55
where exactly does it say he only only wants unique values? just because he was using array_unique doesn't mean anything - he freely admitted he wasn't sure what to use, and the description makes no mention of wanting only unique entries. – Stephen Jan 11 '11 at 17:59
@Will, you are right, values must be unique @Stephen: sorry, it might have been confusing. solution is: array_merge(array_unique(array_merge($a, $b))); because the second array_merge sorts the key from 0 to 4! Thanks all! – Valorized Jan 11 '11 at 18:02
in that case, you don't need two array_merge calls - an array_values call is probably a better choice – Stephen Jan 11 '11 at 18:06
look at the example. – Oliver A. Jan 11 '11 at 18:07
up vote 0 down vote

I am assuming you are working on one dimensional array this worked for me

foreach($b as $i) :
  $a[] = $i;
endforeach;
$ab = array_unique(sort($a));
share|improve this answer
up vote -1 down vote 
$a = array(0 => 0, 1 => 1, 2 => 2);
$b = array(0 => 2, 1 => 3, 2 => 4);

//add any from b to a that do not exist in a
foreach($b as $item){


    if(!in_array($item,$b)){
        $a[] = $item
    }

}

//sort the array
sort($a);
share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.