PHP blog categories duplication - php

Question

I have got a question regarding setting up proper categories for my posts that would be done automatically. I'm using PHP.
Here is my sample example document from the database:
{
"_id" : "css-clearfix-explained",
"title" : "CSS Clearfix Explained",
"category" : [
"CSS/HTML",
" Wordpress"
],
"date_time" : ISODate("2014-08-13T21:03:45.367Z"),
"description" : "Blalalal ",
"content" : " ",
"author" : "Maciej Sitko"
}
So, for that purpse I wrote the code that inserts the categories in the view page, to be more specific, it inserts them into the table. This is the code:
<?php if(!isset($_GET['cat'])) {
$categories = $collection->find();?>
<table class="table table-hover table-striped">
<thead class='table-head' >
<tr ><th colspan='2'>Categories</th></tr>
</thead>
<tbody>
<?php foreach($categories as $category) {
foreach($category as $keys) {
if((is_array($keys)) && (!empty($keys))) {
foreach($keys as $key => $value) { ?>
<tr>
<td><a class="normalize" href="">
<?php echo $keys[$key]; ?></a></td>
<td class="small"> Posts</td>
</tr>
<?php } } } } ?>
</tbody>
</table>
The problem is, and you see it (I bet it), that when it is executed this way there would be duplicates of the categories in the table shown. How can I prevent those categories from repeating themselves in the listing? I know its a rookie question, but I'm still learning.

Answer 1

You could write $category into an array and every iteration - before displaying your data - you could check if $category is already in there. You could use "in_array": http://php.net/manual/de/function.in-array.php
<?php if(!isset($_GET['cat'])) {
$categories = $collection->find();?>
<table class="table table-hover table-striped">
<thead class='table-head' >
<tr ><th colspan='2'>Categories</th></tr>
</thead>
<tbody>
<?php
$uniqueCats = array();
foreach($categories as $category) {
foreach($category as $keys) {
if((is_array($keys)) && (!empty($keys))) {
foreach($keys as $key => $value) {
if( in_array($value, $uniqueCats) ) { continue; }
$uniqueCats[] = $value;
?>
<tr>
<td><a class="normalize" href="">
<?php echo $value; ?></a></td>
<td class="small"> Posts</td>
</tr>
<?php } } } } ?>
</tbody>
</table>
I hope that's what you were looking for :)
The code/variables slightly differs from how I would read the data in the example so I might have misinterpreted your question :)