issue while merging two arrays using array_merge function - php

Question

I have two associative array.
$Array1 = array(
'abc'=> 'abc',
'def'=> 'def'
);
$Array2 = array(
'123'=> '123',
'456'=> '456'
);
I am merging them using array_merge.
$Array3 = array_merge($Array1, $Array2);
Now value of $Array3 is like this.
Array
(
[abc] => abc
[def] => def
[0] => 123
[1] => 456
)
It looks really odd until I read php manual which says Values in the input array with numeric keys will be renumbered with incrementing keys starting from zero in the result array. array_merge manual
My questing How can I merge both array without loosing their associative keys.
Both array can have common KEYS and I don't want to loose my information also. :(

Answer 1

By +:
$Array1 = array(
'abc'=> 'abc',
'def'=> 'def'
);
$Array2 = array(
'123'=> '123',
'456'=> '456'
);
var_dump($Array1 + $Array2);
This will preserve the index, but note this will not overwrite the value of the first array if same key exists in first array.
And if you want the overwrite working, then there is array_replace function for this:
var_dump(array_replace($Array1, $Array2));

Answer 2

Try this code :) it will work
function my_merge($array1,$array2)
{
foreach($array2 as $key => $value)
{
$array1[$key] = $value;
}
return $array1;
}
$Array1 = array(
'abc'=> 'abc',
'def'=> 'def'
);
$Array2 = array(
'123'=> '123',
'456'=> '456'
);
$Array3 = my_merge($Array1, $Array2);

Answer 3

For associative arrays, use
$result = $Array1 + $Array2;
-but note, that for numeric keys this will also re-index:
$Array1 = array(
'abc',
'def'=> 'def'
);
$Array2 = array(
'123',
'456'
);
var_dump($Array1 + $Array2);
//array(3) { [0]=> string(3) "abc" ["def"]=> string(3) "def" [1]=> string(3) "456" }
If you have same keys in your arrays, you can use:
$result = array_reduce(array_keys($Array1), function($c, $x) use ($Array1)
{
$c[$x] = isset($c[$x])
?array_merge((array)$c[$x], [$Array1[$x]])
:$Array1[$x];
return $c;
}, $Array2);