Face problem during get unique value from foreach loop - php

Question

I have faced a problem during get unique value in foreach loop.
Following is my array.
Array
(
[20] => Array
(
[0] => Array
(
[id] => 4
[category_title] => Specialist Range
[parent] => 20
[front_active] => 1
[category_date] => 2019-05-21 04:04:17
)
[1] => Array
(
[id] => 4
[category_title] => Specialist Range
[parent] => 20
[front_active] => 1
[category_date] => 2019-05-21 04:04:17
)
[2] => Array
(
[id] => 4
[category_title] => Specialist Range
[parent] => 20
[front_active] => 1
[category_date] => 2019-05-21 04:04:17
)
[3] => Array
(
[id] => 6
[category_title] => Cater Foil Rolls
[parent] => 20
[front_active] => 1
[category_date] => 2019-05-21 04:04:24
)
)
[21] => Array
(
[8] => Array
(
[id] => 24
[category_title] => Specialist Range
[parent] => 21
[front_active] => 1
[category_date] => 2019-05-21 04:07:59
)
[9] => Array
(
[id] => 24
[category_title] => Specialist Range
[parent] => 21
[front_active] => 1
[category_date] => 2019-05-21 04:07:59
)
)
)
I written following script for getting unique value in loop
$catArray = array();
foreach($catagory_list as $key=>$catagory){
$catArray[$catagory['parent']][$key] = $catagory;
}
ksort($catArray, SORT_NUMERIC);
foreach ($catArray as $key => $value) {
if($key == 20 ){
$catName ='local';
}elseif ($key == 21) {
$catName ='interstate';
}elseif ($key == 22) {
$catName ='wholesale';
}elseif ($key == 23) {
$catName ='tst';
}
//echo $key;
foreach(array_unique($value) as $keys => $valuess){
echo $valuess['category_title'];
?>
<tr class="table_header">
<th><?php echo $catName." - ".$valuess['category_title'];?> </th>
</tr>
<?php
}
}
Problem is 20 has 4 category_title but when i used array_unique Cater Foil Rolls category title of first parent array is not display.
Output only display
Specialist Range not showing (Cater Foil Rolls)

Answer 1

If you are trying to find unique records in this nested array, then I would key your associative array off of the value of "id". If you are only trying to find unique category_title, then I would key off the value of "category_title". In any case I would use the associate array functionality to ensure uniqueness on whatever key you choose. Then you can apply sorting, etc. on the result.
// find first unique records
$result = [];
foreach($parents as $key1=>$child1) {
foreach($child1 as $key2=>$child2) {
if(!isset($result[$child2['id']])) {
$result[$child2['id']] = $child2;
}
}
}
// result = # => record
OR:
// find first unique categories
$result = [];
foreach($parents as $key1=>$child1) {
foreach($child1 as $key2=>$child2) {
if(!isset($result[$child2['category_title']])) {
$result[$child2['category_title']] = $child2;
}
}
}
// result = category => record

Answer 2

I'm not convinced that array_unique works on multi-dimensional arrays.
See this question.