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Wouter Veeneman
Wouter Veeneman

Reputation: 23

PHP shift array order

Im working on something and i need to shift an array with ID's so the ID(person) cant get his own ID unless the "game" is over.

So i got this:

$array = array(
    "2"  => "2",
    "3"  => "3",
    "6"  => "6",
    "8"  => "8",
    "12" => "12",
);

And i want it this way:

 $array = array(
        "2"  => "3",
        "3"  => "6",
        "6"  => "8",
        "8"  => "12",
        "12" => "2",
    );

I'm not a real php hero and the internet isn't helping so far :)

Thx in advance!

Upvotes: 0

Views: 102

Answers (3)

Wouter Veeneman
Wouter Veeneman

Reputation: 23

So after long trying and getting some help from an old friend this is the final result:

    $prev = null;
    $firstIndex = null;
    foreach ($userArr as $i => $user) {
        if (is_null($prev)) {
            $firstIndex = $i;
            $prev = $user;
            continue;
        }
        $userArr[$i] = $prev;
        $prev = $user;
    }
    $userArr[$firstIndex] = $prev;

Upvotes: 0

Progrock
Progrock

Reputation: 7485

<?php

$in = array(
    "2"  => "2",
    "3"  => "3",
    "6"  => "6",
    "8"  => "8",
    "12" => "12",
);

$out = array(
    "2"  => "3",
    "3"  => "6",
    "6"  => "8",
    "8"  => "12",
    "12" => "2",
);

function transpose_values(array $in) {
    $values = array_values($in);
    $first  = array_shift($values);
    $first && array_push($values, $first);
    $out = array_combine($in, $values);

    return $out;
}

assert($out == transpose_values($in));

Upvotes: 1

theruss
theruss

Reputation: 1746

Without knowing what the array's values are supposed to represent, it's a little heard to tell what you're actually trying to do. The way it looks is that a person's (user's?) ID will represent something entirely different given some particular scenario.

Taking your question at face-value therefore, you need a new array, with the values of the old one to be those values, one-position ahead of where they were originally. Use of reset() and next() are the keys here:

$newArray = [];
$firstVal = reset($array);

$i=0;
foreach($array as $key => $val) {
    ++$i;
    // Deal with the last array-element to be given the first's value
    if(count($newArray) === $i) {
        $newArray[$key] = $firstVal;
    } else {
        $newArray[$key] = next($array);
    }
}

Upvotes: 0

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