How to merge mutiple array in a single array - php

Question

As i searched alot but didn't get perfect solution of merging array in one single array.
These arrays are Dynamic (may be increase in future- would 50+). So for that we have to use count() or for loops to fetch and then merge.
Here's my code which i'm trying to resolve over core level. Please anyone tell me how may receive all values in Single array.
Array(
[0] => Array
(
[0] => 123
[1] => 108
[2] => 58
[3] => 23
)
[1] => Array
(
[0] => 93
[1] => 94
[2] => 95
[3] => 172
[4] => 30
)
[2] => Array
(
[0] => 109
[1] => 81
[2] => 79
[3] => 155 )
)`
My expectation of result is: (which i'm unable to get)
Array
(
[0] => 123
[1] => 108
[2] => 58
[3] => 23
[4] => 93
[5] => 94
[6] => 95
[7] => 172
[8] => 30
[9] => 109
[10] => 81
[11] => 79
[12] => 155
)

Answer 1

Use array_merge with splat operator,
$result = array_merge(...$arr);
array_merge — Merge one or more arrays
Splat operator - Since PHP 5.6, you can use splat operator (...) to create simpler variadic functions (functions that take an undefined number of arguments).
Demo
Output:-
Array
(
[0] => 123
[1] => 108
[2] => 58
[3] => 23
[4] => 93
[5] => 94
[6] => 95
[7] => 172
[8] => 30
[9] => 109
[10] => 81
[11] => 79
[12] => 155
)

Answer 2

using array_merge()
$a[0] = [1,2,3];
$a[1] = [4,5,6];
$a[2] = [7,8,9];
$newArr = [];
$newArr = array_merge($a[0], $a[1], $a[2]);
print_r($newArr);
assuming that your array will grow, you can use foreach like this :
$a[0] = [1,2,3];
$a[1] = [4,5,6];
$a[2] = [7,8,9];
$newArr = [];
foreach($a as $index){
foreach($index as $item){
array_push($newArr, $item);
}
}

Answer 3

As i used this technique. I got my answer in just a simple way. of array_flatten
print_r(array_flatten($overall_arr));
function array_flatten($array) {
$return = array();
foreach ($array as $key => $value) {
if (is_array($value)){
$return = array_merge($return, array_flatten($value));
} else {
$return[$key] = $value;
}
}
return $return;
}