pop and push from one associative array to another array - php

Question

I want to pop from array2 and want to push in array1.
But according to some custom requirement.
Now in array1 there is 1st key's readingOrder is 1 and 2nd key's readingOrder is 4.
So i want to push between this two key from array2's first two key.And same process for all other.
and my final array must be like array3.
for example in array1 key[0] readingOrder is 1 and key[1]'s 4. Now i want to push another two key from array2.
for array1 key[2] reading order is 6. so before this key i want to push another one key from array2 and same for further...
array1 is like below
Array
(
[0] => Array
(
[readingOrder] => 1
[id] => 78
)
[1] => Array
(
[readingOrder] => 4
[id] => 76
)
[2] => Array
(
[readingOrder] => 6
[id] => 80
)
)
array2 is like below
Array
(
[0] => Array
(
[id] => 81
[readingOrder] => 2
)
[1] => Array
(
[id] => 82
[readingOrder] => 5
)
[2] => Array
(
[id] => 84
[readingOrder] => 7
)
[3] => Array
(
[id] => 85
[readingOrder] => 8
)
[4] => Array
(
[id] => 86
[readingOrder] => 9
)
[5] => Array
(
[id] => 87
[readingOrder] => 10
)
[6] => Array
(
[id] => 88
[readingOrder] => 11
)
)
Output array3:
Array
(
[0] => Array
(
[readingOrder] => 1
[id] => 78
)
[1] => Array
(
[id] => 81
[readingOrder] => 2
)
[2] => Array
(
[id] => 82
[readingOrder] => 5
)
[3] => Array
(
[readingOrder] => 4
[id] => 76
)
[4] => Array
(
[id] => 84
[readingOrder] => 7
)
[5] => Array
(
[readingOrder] => 6
[id] => 80
)
[6] => Array
(
[id] => 85
[readingOrder] => 8
)
[7] => Array
(
[id] => 86
[readingOrder] => 9
)
[8] => Array
(
[id] => 87
[readingOrder] => 10
)
[9] => Array
(
[id] => 88
[readingOrder] => 11
)
)
Thanks..

Answer 1

You can build your array like that:
$current = 1;
$arr3 = [];
while ( $arr1 && $arr2 ) {
if ( $arr1[0]['readingOrder'] > $current )
$arr3[] = array_shift($arr2);
else
$arr3[] = array_shift($arr1);
$current++;
}
$arr3 = array_merge($arr3, $arr1, $arr2);
print_r($arr3);
Note that this code is destructive for $arr1 and $arr2. If you want to preserve them, copy them before and use the copies instead.

Answer 2

You can do this with usort. First you need to merge the arrays:
$a1 = [
[
'readingOrder' => 1,
'id' => 78
],
[
'readingOrder' => 4,
'id' => 76
],
[
'readingOrder' => 6,
'id' => 80
]
];
$a2 = [
[
'readingOrder' => 2,
'id' => 81
],
[
'readingOrder' => 5,
'id' => 82
],
[
'readingOrder' => 7,
'id' => 84
],
[
'readingOrder' => 8,
'id' => 85
]
];
$a3 = array_merge($a1, $a2);
Then you need to use usort:
usort($a3, function($a,$b) {
if ($a['readingOrder'] == $b['readingOrder']) return 0;
return $a['readingOrder'] < $b['readingOrder'] ? -1 : 1;
});
In PHP 7 you can now use the spaceship operator, which would make the code more clean. Like so:
usort($a3, function($a,$b) {
return $a[0] <=> $b[0];
});
This will then return:
(
[0] => Array
(
[readingOrder] => 1
[id] => 78
)
[1] => Array
(
[readingOrder] => 2
[id] => 81
)
[2] => Array
(
[readingOrder] => 4
[id] => 76
)
[3] => Array
(
[readingOrder] => 5
[id] => 82
)
[4] => Array
(
[readingOrder] => 6
[id] => 80
)
[5] => Array
(
[readingOrder] => 7
[id] => 84
)
[6] => Array
(
[readingOrder] => 8
[id] => 85
)
)