PHP array_merge with numerical keys
Use the +
operator.
Compare array_merge
to +
operator:
<?php
$a1 = array(0=>"whatever",);
$a2 = array(0=>"whatever",1=>"a",2=>"b");
print_r(array_merge($a1,$a2));
print_r($a1+$a2);
?>
Output:
Array
(
[0] => whatever
[1] => whatever
[2] => a
[3] => b
)
Array
(
[0] => whatever
[1] => a
[2] => b
)
The +
operator still works if your associative array has the numerical keys out-of-order:
<?php
$a1 = array(0=>"whatever",);
$a2 = array(1=>"a",0=>"whatever",2=>"b");
print_r(array_merge($a1,$a2));
print_r($a1+$a2);
?>
Output:
Array
(
[0] => whatever
[1] => a
[2] => whatever
[3] => b
)
Array
(
[0] => whatever
[1] => a
[2] => b
)
Notice array_merge
in this case creates a new key. Not desirable...
array_replace
does exactly this!
Pretty easy to write manually:
function array_merge_custom($first, $second) {
$result = array();
foreach($first as $key => $value) {
$result[$key] = $value;
}
foreach($second as $key => $value) {
$result[$key] = $value;
}
return $result;
}
Update: This behaves differently than the union operator (return $first + $second;
) because in this case the second array wins when both have elements with the same key.
However, if you switch the places of the arguments and place the array that you want to "win" in case of conflicts as the first operand, you can get the same behavior. So the function above behaves exactly like return $second + $first;
.