Remove/unset every other key in multidimensional array but preserve keys - php

Question

I have a long multidimensional array with timestamps as keys which contain arrays of values. Something like this but with more timestamps:
array(3) {
[1502609400]=>
array(2) {
["Item1"]=>
array(1) {
["PRICE"]=>
float(100)
}
["Item2"]=>
array(1) {
["PRICE"]=>
float(50)
}
}
[1502611200]=>
array(2) {
["Item1"]=>
array(1) {
["PRICE"]=>
float(200)
}
["Item2"]=>
array(1) {
["PRICE"]=>
float(150)
}
}
[1502613000]=>
array(2) {
["Item1"]=>
array(1) {
["PRICE"]=>
float(500)
}
["Item2"]=>
array(1) {
["PRICE"]=>
float(250)
}
}
How can I remove every every second array of the array without losing the keys as timestamp? So I end up with this:
array(3) {
[1502609400]=>
array(2) {
["Item1"]=>
array(1) {
["PRICE"]=>
float(100)
}
["Item2"]=>
array(1) {
["PRICE"]=>
float(50)
}
}
[1502613000]=>
array(2) {
["Item1"]=>
array(1) {
["PRICE"]=>
float(500)
}
["Item2"]=>
array(1) {
["PRICE"]=>
float(250)
}
}
If I use a for loop and unset every second key I lose all the keys and end up with 0, 1, 2 etc. instead of the timestamp.

Answer 1

In a loop, check for index and unset every second element:
You can use custom $index variable, like this:
$index = 0; // points to first element
foreach ($array as $key => $value) {
if ($index % 2 != 0) { //check for un-even
unset($array[$key]);
}
$index++; // move pointer to next element
}

Answer 2

$i=1 // where the key to remove
$x=0; //loop to determine the key position
foreach ($array as $key=>$value){
if($x==$i){
unset($array[$key]);
}
$x++;
}

Answer 3

In that kind of case, a simple foreach can be more efficient perfwise than a standard function :
foreach ($array as $key => $val) {
if (array_key_exists('Item2', $val)) {
unset($val['Item2']);
}
}