How to make group (if specific field are same text) in loop? - php

Question

I tried render data in loop and if extend_tag field have same text group in one container.
I only know hard code like below, loop data base on how many known extend_tag group, but actually the extend_tag numbers is unknown might be tag_ and any digit , any idea how to solve it?
data
[tag] => Array (
[0] => Array (
[id] => 1
[extend_tag] => tag_0
)
[1] => Array (
[id] => 2
[extend_tag] => tag_11
)
[2] => Array (
[id] => 3
[extend_tag] => tag_4
)
)
<ul class="container">
<?php foreach($rows['tag'] as $eachRowsTag) { ?>
<?php if ($eachRowsTag['extend_tag'] == 'tag_0') { ?>
<li>><?php echo $eachRowsTag['id']; ?></li>
<?php } ?>
<?php } ?>
</ul>
<ul class="container">
<?php foreach($rows['tag'] as $eachRowsTag) { ?>
<?php if ($eachRowsTag['extend_tag'] == 'tag_1') { ?>
<li>><?php echo $eachRowsTag['id']; ?></li>
<?php } ?>
<?php } ?>
</ul>
...

Answer 1

Why not group them first, then iterate over the resulting array. Something like the following.
foreach ($tags as $tag) {
$grouped[$tag['extend_tag']][] = $tag;
}
// Now $grouped is something along the lines of:
// [
// 'tag_0' => [
// [ 'id' => 1, 'extend_tag' => 'tag_0'],
// ..
// ],
// ..
// ]
foreach($grouped as $extend_tag => $tags) {
echo "All tags in $extended_tag.";
foreach($tags as $tag) {
echo $tag['id'];
}
}
// For something like:
// All tags in tag_0.
// 1
// 4
// All tags in tag_1.
// ..