how to check if the element of an array is changed - php

Question

Sorry I don't know the actual title of my question. I have a problem with a php array.
my array is like :
$Array =
(
[0] => Array
(
[Product] => Array
(
[cat_id] => 7
[subcat_id] => 1
)
)
[1] => Array
(
[Product] => Array
(
[cat_id] => 7
[subcat_id] => 1
)
)
[2] => Array
(
[Product] => Array
(
[cat_id] => 8
[subcat_id] => 2
)
)
[3] => Array
(
[Product] => Array
(
[cat_id] => 9
[subcat_id] => 3
)
)
[4] => Array
(
[Product] => Array
(
[cat_id] => 9
[subcat_id] => 3
)
)
)
Now I want to insert
[Subcat]=>'changed'
if the subcat_id is changed . How to check if the subcat_id is changed on the next key value.please help.
I have tried this :
$sub_cat_last = '';
foreach ($Array as $key => $p) {
$sub_cat = $p['Product']['subcat_id'];
if($sub_cat != $sub_cat_last){
$Array[$key]['Subcat'] = 'change';
$sub_cat_last = $p['Product']['subcat_id'];
}
}
But not working properly.
I want my array like :
Array
(
[0] => Array
(
[Product] => Array
(
[cat_id] => 7
[subcat_id] => 1
)
)
[1] => Array
(
[Product] => Array
(
[cat_id] => 7
[subcat_id] => 1
)
)
[2] => Array
(
[Product] => Array
(
[Subcat] => change
)
)
[3] => Array
(
[Product] => Array
(
[cat_id] => 8
[subcat_id] => 2
)
)
[4] => Array
(
[Product] => Array
(
[Subcat] => change
)
)
[5] => Array
(
[Product] => Array
(
[cat_id] => 9
[subcat_id] => 3
)
)
[6] => Array
(
[Product] => Array
(
[cat_id] => 9
[subcat_id] => 3
)
)
[7] => Array
(
[Product] => Array
(
[Subcat] => change
)
)
)
Is this possible.

Answer 1

How about:
$Array = Array(
0 => Array(
'Product' => Array(
'cat_id' => 7,
'subcat_id' => 1,
)
),
1 => Array(
'Product' => Array(
'cat_id' => 7,
'subcat_id' => 1,
)
),
2 => Array(
'Product' => Array(
'cat_id' => 8,
'subcat_id' => 2,
)
),
);
$prev_id = $Array[0]['Product']['subcat_id'];
$result = array(0 => $Array[0]);
for($i = 1; $i < count($Array); $i++) {
if ($Array[$i]['Product']['subcat_id'] != $prev_id) {
$result[]['Product']['subcat'] = 'change';
}
$result[] = $Array[$i];
$prev_id = $Array[$i]['Product']['subcat_id'];
}
$result[]['Product']['subcat'] = 'change';
print_r($result);
Output:
Array
(
[0] => Array
(
[Product] => Array
(
[cat_id] => 7
[subcat_id] => 1
)
)
[1] => Array
(
[Product] => Array
(
[cat_id] => 7
[subcat_id] => 1
)
)
[2] => Array
(
[Product] => Array
(
[subcat] => change
)
)
[3] => Array
(
[Product] => Array
(
[cat_id] => 8
[subcat_id] => 2
)
)
[4] => Array
(
[Product] => Array
(
[subcat] => change
)
)
)

Answer 2

save previous cat_id and subcat_id, check when cat_id added one. This suppose you cat_id is in sequence, added 0 or 1 each step.
$preValue = array('cat_id' => 0, 'subcat_id' => 0);
$changed = false;
foreach ($Array as $item) {
$product = $item['Product'];
if($preValue['cat_id'] != 0 && $product['cat_id'] == $preValue['cat_id'] + 1 && $product['subcat_id'] != $preValue['subcat_id'])
{
$changed = true;
break;
}
$preValue['cat_id'] = $product['cat_id'];
$preValue['subcat_id'] = $product['subcat_id'];
}

Answer 3

This will do what you are looking for:
$old_subcat_id = null;
$newArray = Array();
foreach ($Array as $item) {
$subcat_id = $item['Product']['subcat_id'];
if ($subcat_id != $old_subcat_id) {
//do something here
echo "subcat_id has changed from [$old_subcat_id] to [$subcat_id]<br>";
if ($old_subcat_id != null) {
$newArray[]['Product']['Subcat'] = 'change';
}
$old_subcat_id = $subcat_id;
}
$newArray[] = $item;
}