Add elements to existing array - php

Question

I have an array that looks like this
array(3) {
[0]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(2) "2"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
[1]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(1) "5"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
[2]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(1) "9"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
}
As you can see it consists of sort, date, month and year. I want to add new element into the same array with value "day" +1.
If the 8th of august 2015 is in array the it should also include 9th of august 2015.
I need a way to extract values, calculate new date and put back in all dates.
The result should look like this:
array(3) {
[0]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(2) "2"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
[1]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(1) "5"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
[2]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(1) "9"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
[3]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(2) "3"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
[4]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(1) "6"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
[5]=>
array(4) {
["sort"]=>
string(0) ""
["day"]=>
string(1) "10"
["month"]=>
string(1) "8"
["year"]=>
string(4) "2015"
}
}
Ideally it should also exclude new dates, if allready identical date is in the array.

Answer 1

Create array with new items and merge it with old array
$temp = array();
foreach($array as $item)
$temp[] = array_replace($item, array("day" => $item["day"]+1));
$res = array_merge($array, $temp);
To exlude repeating day
$days = array_reduce($array,
function($a, $i) { $a[$i['day']] = 1; return $a; ; },
array());
$temp = array();
foreach($array as $item)
if (! isset($days[$item["day"]+1]))
$temp[] = array_replace($item, array("day" => $item["day"]+1));
$res = array_merge($array, $temp);