Quick question - merging two or more arrays without reindexing

[eluser]TheFuzzy0ne[/eluser]
Hi everyone. I need to merge two arrays together without the keys being reindexed. I know this can be done, but I cannot for the life of me remember how to go about doing it without looping through the array(s) to be added and adding them one by one. Please could someone tell me the correct function to use?

Many thanks in advance.

[eluser]umefarooq[/eluser]
try array_merge() hope it will work for you

[eluser]Dam1an[/eluser]
I'm still half asleep, so might understand this wrong
Is what you're trying to acheive is merge
1,3,4,6,8,9 and 1,4,5,6 into 1,1,3,4,4,5,6,6,8,9?

[eluser]TheFuzzy0ne[/eluser]
OK, an example:

Code:

$arr1 = array(
    '1' => 'val 1',
    '2' => 'val 2',
);

$arr2 = array(
    '10' => 'val 10',
    '11' => 'val 11',
);

When there are merged together, I should have an array like this:

Code:

$arr1 = array(
    '1' => 'val 1',
    '2' => 'val 2',
    '10' => 'val 10',
    '11' => 'val 11',
);

But instead, I get an array like this:

Code:

$arr1 = array(
    '0' => 'val 1',
    '1' => 'val 2',
    '2' => 'val 10',
    '3' => 'val 11',
);

Note: The keys have been reindexed. I'm trying to merge the two together without using a loop, whilst keeping the keys intact.

Thanks again.

[eluser]Dam1an[/eluser]
Would this not cause a problem when both arrays have the same key (eg both have index 0)? Would you expect to overwrite it, increment the key of one to avoid crash etc?

[eluser]TheFuzzy0ne[/eluser]
OK, I think I've solved it.

Code:

print_r($arr1 + $arr2);

#Output:
Array
(
    [1] => val 1
    [2] => val 2
    [10] => val 10
    [11] => val 11
)

I'd still be interested to know what PHP function the + construct calls, though.

[eluser]TheFuzzy0ne[/eluser]
[quote author="Dam1an" date="1243963231"]Would this not cause a problem when both arrays have the same key (eg both have index 0)? Would you expect to overwrite it, increment the key of one to avoid crash etc?[/quote]

There wouldn't be a problem, as the keys are UIDs, but yes, if by some freak of nature the key existed, it should just be overwritten.

[eluser]Evil Wizard[/eluser]
[quote author="Dam1an" date="1243963231"]Would this not cause a problem when both arrays have the same key (eg both have index 0)? Would you expect to overwrite it, increment the key of one to avoid crash etc?[/quote]
That could be avoided with

Code:

if(!count(array_diff_assoc($array1, $array2)) {
    $array3 = $array1 + $array2
}

If any keys are in both arrays it wont add them together.

[eluser]xwero[/eluser]
The array_diff_key function could be used to merge arrays, it preserves the keys and if there is a non unique key found it will be removed.

[eluser]Dam1an[/eluser]
Looking on the php docs (here) that only seems to work one way :-S

Code:

<?php
$array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'   => 8);

var_dump(array_diff_key($array1, $array2));
?>

Results in

Code:

array(2) {
  ["red"]=>
  int(2)
  ["purple"]=>
  int(4)
}

Whereas you'd want Yellow and Cyan from the second array in this case