add items to multidimensional array programmatically in php - php

Question

I have the following array
$a = array(0 => 'Item',
1 => 'Wattles',
2 => 'Types',
3 => 'Compost',
4=> 'Estimated',
5 => '123',
6 => 'Actual',
7 => '12',
);
That is sorted with the following code.
echo "<pre>";
print_r($a);
$a_len = count($a);
$fnl = array();
$i = 0;
while($i<$a_len){
$fnl[$a[$i]] = $a[++$i];
$i++;
}
print_r($fnl);
It prints correctly
Array
(
[Item] => Wattles
[Types] => Compost
[Estimated Qty] => 123
[Actual Qty] => 12
)
until i add multiple entries.
Array
(
[0] => Item
[1] => Wattles
[2] => Types
[3] => Compost
[4] => Estimated Qty
[5] => 123
[6] => Actual Qty
[7] => 12
[8] => Item
[9] => Silt Fence
[10] => Types
[11] => Straw
[12] => Estimated Qty
[13] => 45
[14] => Actual Qty
[15] => 142
)
I need to make this add items in a multidimensional array.
$items = array
(
array("Wattles","Silt Fence), //items
array("Compost","Straw"), //types
array(123,45), //estimated quantity
array(12,142) //actual quantity
);
There are a few given numbers. There are exactly 4 entries (8 items) before the list repeats itself.
I have been stuck on this portion for hours, and don't know how to get my code working as I want it to.

Answer 1

To get the expected result with string keys you can do:
foreach(array_chunk($a, 2) as $pairs) {
$result[$pairs[0]][] = $pairs[1];
}
Yields:
Array
(
[Item] => Array
(
[0] => Wattles
[1] => Silt Fence
)
[Types] => Array
(
[0] => Compost
[1] => Straw
)
[Estimated] => Array
(
[0] => 123
[1] => 45
)
[Actual] => Array
(
[0] => 12
[1] => 142
)
)
Then if you want it numerically indexed:
$result = array_values($result);

Answer 2

You have your structure for a multidimensional array wrong. You should construct your array like this:
$a = array(
0 => array(
'Item' => 'Wattles',
'Types' => 'Compost',
'Estimated' => 123,
'Actual' => 12
)
);
Then to add to it:
$a[] = array(
'Item' => 'Silt Fence',
'Types' => 'Straw',
'Estimated' => 45,
'Actual' => 142
);
Render it out to see the results which are what I think you are looking for.
print_r($a);
I can post a link if you want to learn how to sort multidimensional arrays by sub-array values if you need.