Merge Subarray (PHP 5.3.3) [duplicate] - php

Question

This question already has answers here:
Merge all sub arrays into one [duplicate]
(3 answers)
Closed 2 years ago.
I want to merge all sub arrays of an array in an older project that requires >=5.3.3.
The array mentioned above looks like this:
$array = Array (
Array
(
[0] => 26
[1] => 644
)
Array
(
[0] => 20
[1] => 26
[2] => 644
)
Array
(
[0] => 26
)
Array
(
[0] => 47
)
Array
(
[0] => 47
[1] => 3
[2] => 18
)
Array
(
[0] => 26
[1] => 18
)
Array
(
[0] => 26
[1] => 644
[2] => 24
[3] => 198
[4] => 8
[5] => 6
[6] => 41
[7] => 31
)
Array
(
[0] => 26
[1] => 644
[2] => 24
[3] => 198
[4] => 12
[5] => 25
[6] => 41
[7] => 31
)
Array
(
[0] => 198
)
Array
(
[0] => 198
)
Array
(
[0] => 899
))
Now, I'm wondering how I could merge all of those Subrrays into one that looks like this:
Array
(
[1] => 26
[2] => 644
[3] => 20
[4] => 26
[5] => 644
[6] => 26
[7] => 47
[8] => 47
[9] => 3
[10] => 18
[11] => 26
[12] => 18
[13] => 26
[14] => 644
[15] => 24
[16] => 198
[17] => 8
[18] => 6
[19] => 41
[20] => 31
[21] => 26
[22] => 644
[23] => 24
[24] => 198
[25] => 12
[26] => 25
[27] => 41
[28] => 31
[29] => 198
[30] => 198
[31] => 899
)
I know how this could work on a more up to date PHP version. So far on this older version I've tried the following:
print_r(array_merge($array, $emptyArray));
But I get the exact same Array returned.
I also tried something like this:
$result_arr = array();
foreach ($array as $sub_arr) $result_arr = array_merge($result_arr, $sub_arr);
$result_arr = array_unique($result_arr);
print_r($result_arr);
Which tells me my second argument is not an array?
I'm a bit confused and hope someone can shed some light on this issue.

Answer 1

this function, I think, will do it well.
function array_flatten(array $array)
{
$result = array();
foreach ($array as $key => $value) {
if (is_array($value)) {
$result = array_merge($result, array_flatten($value));
} else {
$result = array_merge($result, array($key => $value));
}
}
return $result;
}
All you have to do is send your array as a parameter of the function, and display the result.
$arrayToFlatt = Array(
Array(26, 644),
Array(20, 26, 644),
Array(26),
Array(47),
Array(47, 3, 18),
Array(26, 18),
Array(26, 644, 24, 198, 8, 6, 41, 31),
Array(26, 644, 24, 198, 12, 25, 41, 31),
Array(198),
Array(198),
Array(899)
);
echo '<pre>';
print_r(array_flatten($arrayToFlatt));
echo '</pre>';
Working since PHP 4

Answer 2

You could use array_walk_recursive(), which will visit each leaf node of the input array, then add this value to an output array...
$output = array();
array_walk_recursive($array, function ($data) use (&$output) {
$output[] = $data;
});
print_r($output);

Answer 3

Your foreach approach is fine, and works for me. But I don't see why you are filtering with array_unique.
<?php
$data =
[
[1,3,5,7],
[2,4,6,8],
[1,2,4,5]
];
$output = [];
foreach ($data as $sub) {
$output = array_merge($output, $sub);
}
var_export($output);
Output:
array (
0 => 1,
1 => 3,
2 => 5,
3 => 7,
4 => 2,
5 => 4,
6 => 6,
7 => 8,
8 => 1,
9 => 2,
10 => 4,
11 => 5,
)
To flatten with the splat (Php 5.6):
$output = array_merge(...$data);
For pre-splat versions:
$output = call_user_func_array('array_merge', $data);
Or array_reduce:
$output = array_reduce($data, 'array_merge', []);
If in doubt foreach:
$output = [];
foreach($data as $v)
foreach($v as $n)
$output[] = $n;
All the above result in the same zero indexed array.