Create groups of values from array values

Question

I will do my best to explain this idea to you. I have an array of values, i would like to know if there is a way to create another array of combined values. So, for example:

If i have this code:

array('ec','mp','ba');

I would like to be able to output something like this:

'ec,mp', 'ec,ba', 'mp,ba', 'ec,mp,ba'

Is this possible? Ideally i don't want to have duplicate entries like 'ec,mp' and 'mp,ec' though, as they would be the same thing

Is this the same as what you need? http://stackoverflow.com/questions/10572546/php-merge-arrays-with-only-not-duplicated-values — johnny, Jun 06 '15 at 14:09
@Rizier123 i havent tried anything because i don't know where to start with this logic if i'm honest — Andy Holmes, Jun 06 '15 at 14:10
@johnny no because that's merging 2 different arrays into one, i'd like to use this one array and create a new one with paired values — Andy Holmes, Jun 06 '15 at 14:11
It's not entirely what you want: http://stackoverflow.com/a/3200283/3933332 But I hope it gives you some ideas :) — Rizier123, Jun 06 '15 at 14:12
what is the exact output that you're looking for? do you want all the couples? Or all the subsets with cardinality bigger than one? — marcosh, Jun 06 '15 at 14:13
http://stackoverflow.com/questions/10085019/creating-all-combination-in-php — splash58, Jun 06 '15 at 14:14
@marcosh i've already shown the desired output in the question — Andy Holmes, Jun 06 '15 at 14:14
@AndyHolmes I was asking for a clarification, since it's not clear to me what needs to happen if, for example, the starting array has 4 elements and not 3 — marcosh, Jun 06 '15 at 14:15
You want the power set http://stackoverflow.com/questions/6092781/finding-the-subsets-of-an-array-in-php — CrayonViolent, Jun 06 '15 at 14:16
@CrayonViolent That was a good one. Good question too. https://www.mathsisfun.com/sets/power-set.html — johnny, Jun 06 '15 at 14:28

score 1 · Answer 1 · answered Jun 06 '15 at 14:15

1

You can take an arbitrary decision to always put the "lower" string first. Once you made this decision, it's just a straight-up nested loop:

$arr = array('ec','mp','ba');
$result = array();
foreach ($arr as $s1) {
    foreach ($arr as $s2) {
        if ($s1 < $s2) {
            $result[] = array($s1, $s2);
        }
    }
}

answered Jun 06 '15 at 14:15

Mureinik

297,002
52
306
350

This is great, only thing it doesn't do is out put all array values into one combination (`'ec,mp,ba'`) but i can work on that. Thank you for a quick solution :) – Andy Holmes Jun 06 '15 at 14:20

score 0 · Answer 2 · answered Jun 06 '15 at 14:19

You can do it as follows:

$arr = array('ec','mp','ba', 'ds', 'sd', 'ad');

$newArr = array();

foreach($arr as $key=>$val) {
        if($key % 2 == 0) {
                $newArr[] = $val;
        } else {
                $newArr[floor($key/2)] = $newArr[floor($key/2)] . ',' . $val;
        }
}

print_r($newArr);

And the result is:

Array
(
    [0] => ec,mp
    [1] => ba,ds
    [2] => sd,ad
)

score -1 · Answer 3 · answered Jun 06 '15 at 14:18

Have you looked at the function implode

<?php

    $array = array('ec','mp','ba');
    $comma_separated = implode(",", $array);

    echo $comma_separated; // ec,mp,ba
?>

You could use this as a base for your program and what you are trying to achieve.

Create groups of values from array values

3 Answers3