PHP combine multiple arrays into multidimensional array - php

Question

I am writing code in PHP to collect all the hashtags which I've used in all my media posts and see in how many posts I've used the hashtag and how many likes the post with that hashtag received in total.
I have collected all of the media posts in my database and are now able to export this information. Here is an example of the multidimensional array which is being output:
Array
(
[0] => Array
(
[id] => 1
[caption] => #londra #london #london_only #toplondonphoto #visitlondon #timeoutlondon #londres #london4all #thisislondon #mysecretlondon #awesomepix #passionpassport #shootermag #discoverearth #moodygrams #agameoftones #neverstopexploring #beautifuldestinations #artofvisuals #roamtheplanet #jaw_dropping_shots #fantastic_earth #visualsoflife #bdteam #nakedplanet #ourplanetdaily #earthfocus #awesome_earthpix #exploretocreate #londoneye
[likesCount] => 522
)
[1] => Array
(
[id] => 2
[caption] => #londra #london #london_only #toplondonphoto #visitlondon #timeoutlondon #londres #london4all #thisislondon #mysecretlondon #awesomepix #passionpassport #shootermag #discoverearth #moodygrams #agameoftones #neverstopexploring #beautifuldestinations #artofvisuals #roamtheplanet #jaw_dropping_shots #fantastic_earth #visualsoflife #bdteam #nakedplanet #ourplanetdaily #earthfocus #awesome_earthpix #harrods #LDN4ALL_One4All
[likesCount] => 1412
)
)
I am able to separate these hashtags out using the following function:
function getHashtags($string) {
$hashtags= FALSE;
preg_match_all("/(#\w+)/u", $string, $matches);
if ($matches) {
$hashtagsArray = array_count_values($matches[0]);
$hashtags = array_keys($hashtagsArray);
}
return $hashtags;
}
Now I want to create a multidimensional array for each hashtag which should look like this:
Array
(
[0] => Array
(
[hash] => #londra
[times_used] => 2
[total_likes] => 153
)
[1] => Array
(
[hash] => #london
[times_used] => 12
[total_likes] => 195
)
)
I am quite new to this and not sure how to achieve this. Help and suggestions are appreciated!

Answer 1

It would be easier to use the hashtags as keys in your array. You can
transform it later to your final format if you want to. The idea is to
traverse your input array and within each element iterate on the given
hashtags string, increasing counters.
And if your hashtags are always in a string like that, separated by
whitespace, you can also get an array of then with explode() or
preg_split() for finer control.
$posts = # your input array
$tags = [];
foreach ($posts as $post) {
$hashtags = explode(' ', $post['caption']);
foreach ($hashtags as $tag) {
if (!key_exists($tag, $tags)) {
# first time seeing this one, initialize an entry
$tags[$tag]['counter'] = 0;
$tags[$tag]['likes'] = 0;
}
$tags[$tag]['counter']++;
$tags[$tag]['likes'] += $post['likesCount'];
}
}
Transforming to something closer to your original request:
$result = array_map(function($hashtag, $data) {
return [
'hash' => $hashtag,
'times_used' => $data['counter'],
'total_likes' => $data['likes'],
'average_likes' => $data['likes'] / $data['counter'],
];
}, array_keys($tags), $tags);