Inject an array inbetween another array in PHP - php

Question

I have to merge (inject) an array in between another array.
Injected array is adding an additional level at the top.
Actual code is different, but here I have created a simple example to illustrate the issue I am facing.
Here is the sample code:
$mid_array = [
'heading3' => 'Heading 3',
'heading4' => 'Heading 4'
];
$main_array = [
'heading1' => 'Heading 1',
'heading2' => 'Heading 2',
$mid_array,
'heading5' => 'Heading 5'
];
echo '<pre>'; print_r($main_array); echo '</pre>';
Output I am getting
Array
(
[heading1] => Heading 1
[heading2] => Heading 2
[0] => Array
(
[heading3] => Heading 3
[heading4] => Heading 4
)
[heading5] => Heading 5
)
This is what exactly I need
Array
(
[heading1] => Heading 1
[heading2] => Heading 2
[heading3] => Heading 3
[heading4] => Heading 4
[heading5] => Heading 5
)

Answer 1

Based on the assumption that your arrays might change but will continue to have keys like heading1, heading2 this would be my solution
$newArray = array_merge($main_array,$mid_array);
ksort($newArray);
this will return the array you need.

Answer 2

I think you are looking for array_splice, as such:
array_splice($main_array, 2, 0, $mid_array);
Note: array_splice does not preserve keys, if keys are important to you, use following:
function array_insert(&$input, array $arrayToAdd, int $atPosition) {
$before = array_slice($input, 0, $atPosition, true);
$after = array_slice($input, $atPosition, null, true);
$input = $before + $arrayToAdd + $after;
}
Usage
array_insert($main_array, $mid_array, 2);

Answer 3

I think you are looking for the array_merge functionality.
http://php.net/manual/en/function.array-merge.php

Answer 4

You can use array_reduce:
$after = 'heading2';
$result = array_reduce(
array_keys($main_array),
function ($carry, $key) use ($main_array, $after, $mid_array) {
$carry[$key] = $main_array[$key];
return $key === $after
? array_merge($carry, $mid_array)
: $carry;
},
[]
);
Here is the demo.

Answer 5

If key ordering presents a problem (with something like array_merge) you can flatten the inserted array by walking it recursively. You walk along the tips plucking what you need as you go.
<?php
$insert = [
'foo' => 'And it\'s been the ruin of many a poor boy',
'bar' => 'And god I know I\'m one'
];
$inserted = [
'big' => 'There is a house in New Orleans',
'fat' => 'They call the rising sun',
$insert,
'mama' => 'My mother was a taylor'
];
$flattened = [];
array_walk_recursive(
$inserted,
function($v, $k) use (&$flattened) {
$flattened[$k] = $v;
}
);
var_export($flattened);
Output:
array (
'big' => 'There is a house in New Orleans',
'fat' => 'They call the rising sun',
'foo' => 'And it\'s been the ruin of many a poor boy',
'bar' => 'And god I know I\'m one',
'mama' => 'My mother was a taylor',
)