How to merge multiple arrays in array without duplicates - php

Question

I am a newbie in this and I have read lots of stuff about this matter (including some topics here), before starting this topic, but I do not quite get it yet, so I will ask for some help (if it is possible) :)
So, in the column that I want to print I have values like this on every row:
value1|value2|value5|value12|value25
value3|value5|value12|value14|value26|value32|value55
value1|value2|value14|value26|value31
The number of rows can be 3 or 1500+... So I want to merge the arrays and print those values sorted and without duplicates: value1, value2, value3, value5, value12, etc...
I have tried to explode the arrays, but I could not find out how to assign a variable to every array and merge them and all I have done is to print all values:
foreach ($rows as $areas) {
foreach (explode('|', $areas->value) as $area) {
var_dump($area);
}
}
Afterwards I have read somewhere this will be very slow if I have many rows (and I am going to have thousands), so I am stuck here and I do not know what else I could do...
I will appreciate any help and direction that you can give me, because it is too hard for me and I can not do it without help
Thank you in advance

Answer 1

You can store each value of your exploded string as key (if it's not an object nor array), it store only unique values. Then you have to just use array_keys() to get keys and sort returned array:
$rows = array(
'value1|value2|value5|value12|value25',
'value3|value5|value12|value14|value26|value32|value55',
'value1|value2|value14|value26|value31'
);
$results = array();
foreach ($rows as $row) {
$items = explode('|', $row);
foreach ($items as $item) {
$results[$item] = 0;
}
}
$results = array_keys($results);
sort($results, SORT_NATURAL);
Live demo on eval.in

Answer 2

There are two ways of doing this:
<?php
$str = 'value1|value2|value5|value12|value25';
$str1 = 'value3|value5|value12|value14|value26|value32|value55';
$str2 = 'value1|value2|value14|value26|value31';
//-- Method 1: Concat and make a single string and then explode and make a single array
$finalString = $str . '|' . $str1 . '|' . $str2;
print_r(array_unique(explode('|', $finalString)));
//-- Method 2: explode first and then merge into a single array
$strArr = explode('|', $str);
$strArr1 = explode('|', $str1);
$strArr2 = explode('|', $str2);
print_r(array_unique(array_merge($strArr, $strArr1, $strArr2)));