Conditional remove adjacent duplicates from array - php

Question

I have following code that removes adjacent duplicates from the $myArray
<?php
$myArray = array(
0 => 0,
1 => 0,
2 => 1,
5 => 1,
6 => 2,
7 => 2,
8 => 2,
9 => 0,
10 => 0,
);
$previtem= NULL;
$newArray = array_filter(
$myArray,
function ($currentItem) use (&$previtem) {
$p = $previtem;
$previtem= $currentItem;
return $currentItem!== $p ;
}
);
echo "<pre>";
print_r($newArray);
?>
It works perfectly fine, but I have to change a condition bit for value 2. That means for other values we can pick first occurrence and ignore the others. But for 2, we need to pick last occurrence and ignore others.
So required output is
Array
(
[0] => 0 //first occurrence of 0 in $myArray
[2] => 1 //first occurrence of 1 in $myArray
[8] => 2 //last occurrence of 2 in the $myArray
[9] => 0 //first occurrence of 0 in $myArray
)
How to modify my code to achieve above result??
In reality I have multidimensional array, but for better explanation I have used single dimensional array here in the question.
UPDATE
My actual array is
$myArray = array(
0 => array("Value"=>0, "Tax" => "11.00"),
1 => array("Value"=>0, "Tax" => "12.00"),
2 => array("Value"=>1, "Tax" => "13.00"),
5 => array("Value"=>1, "Tax" => "14.00"),
6 => array("Value"=>2, "Tax" => "15.00"),
7 => array("Value"=>2, "Tax" => "16.00"),
8 => array("Value"=>2, "Tax" => "17.00"),
9 => array("Value"=>0, "Tax" => "18.00"),
10 => array("Value"=>0, "Tax" => "19.00"),
);
And my actual code
$previtem= NULL;
$newArray = array_filter(
$myArray,
function ($currentItem) use (&$previtem) {
$p["Value"] = $previtem["Value"];
$previtem["Value"] = $currentItem["Value"];
return $currentItem["Value"]!== $p["Value"] ;
}
);
Thanks

Answer 1

This should do what you are looking for.
function array_filter($a) {
$na = array();
$first = true;
$p = null;
$wantlast = false;
foreach ($a as $v) {
if ($wantlast) {
($v != $p) ? $na[] = $p: null;
}
$wantlast = ($v == 2) ? true : false;
if (!$wantlast) {
(($v != $p) || ($first))? $na[] = $v : null;
}
$p = $v;
$first = false;
}
return $na;
}

Answer 2

$myArray = array(
0 => 0,
1 => 0,
2 => 1,
5 => 1,
6 => 2,
7 => 2,
8 => 2,
9 => 0,
10 => 0,
);
$previtem= NULL;
$newArray = array_filter(
$myArray,
function ($currentItem, $key) use (&$previtem,$myArray) {
$p = $previtem;
if($currentItem != 2){
$previtem = $currentItem;
}else{
$lastkey = array_search(2,(array_reverse($myArray, true)));
if($key != $lastkey)
$currentItem = $previtem;
}
return $currentItem!== $p ;
}, ARRAY_FILTER_USE_BOTH
);
echo "<pre>";
print_r($newArray);