PHP Permutations with exception of similar sequence - php

Question

My permutation/combinations of data
$combinations = [[]];
$data = [
['alteration1', 'alteration2', 'alteration3', 'alteration4' ... upto 5 each],
['alteration1', 'alteration5', 'alteration6', 'alteration7' ... upto 5 each],
['alteration8', 'alteration9', 'alteration10', 'alteration5' ... upto 5 each],
... upto 6 max
];
$length = count($data);
for ($count = 0; $count < $length; $count++) {
$tmp = [];
foreach ($combinations as $v1) {
foreach ($data[$count] as $v2)
$tmp[] = array_merge($v1, [$v2]);
}
$combinations = $tmp;
}
print_r($combinations);
The script would generate such sets
0 => array:3 [▼
0 => "alteration1"
1 => "alteration1"
2 => "alteration8"
]
1 => array:3 [▼
0 => "alteration1"
1 => "alteration1"
2 => "alteration9"
]
... the issue begins when I start getting the same sequences of data in my case array index 0 and 20 would be exactly the same despite any position.
20 => array:3 [▼
0 => "alteration8"
1 => "alteration1"
2 => "alteration1"
]
21 => array:3 [▼
0 => "alteration1"
1 => "alteration9"
2 => "alteration1"
]
$final = []; // remove duplicates
The basic idea is to keep $combinations array's unique (alteration1,alteration2,alteration3) is equal to (alteration3,alteration1,alteration2) therfore it should be skipped in the $final array. I haven't really found anything around SO and google. Thanks for the help. $data dimentions [ from 1 - 6 ], each array inside can be [ 1 - 6 ]. Following script might not be working as expected .
http://sandbox.onlinephpfunctions.com/code/3ad5084386c2185f7619aaac152b638873039ee8

Answer 1

We iterate over the data and find unique elements first for each set using array_unique.
We then natsort them to get a sorted form and serialize them using implode(). By doing this, we would get the same serialized code for sets ABC,CBA,BAC etc.
We then find duplicates using keys check inside a variable, say $set. If the serialized key is set, we exclude it from the results, else we include it in our final results.
Snippet:
<?php
$data = [
['alteration1', 'alteration4',],
['alteration2','alteration3'],
['alteration2','alteration3'],
[]
];
$combinations = [[]];
foreach($data as $index => $current_data){
$current_data = array_unique($current_data);
if(empty($current_data)) continue;
$temp_combinations = [];
foreach($current_data as $value){
foreach($combinations as $each_combination){
$temp_combinations[] = array_merge($each_combination,[$value]);
}
}
$combinations = $temp_combinations;
}
$set = [];
$unique_combinations = [];
foreach($combinations as $each_combination){
natsort($each_combination);
$serialized_form = implode(",",$each_combination);
if(isset($set[$serialized_form])) continue;
if(empty($each_combination)) continue;
$unique_combinations[] = $each_combination;
$set[$serialized_form] = true;
}
print_r($unique_combinations);
Demo: https://3v4l.org/Do6oH