PHP dereference array elements

Question

I have 2 arrays.

$result = array();
$row = array();

Row's elements are all references and is constantly changing. For each iteration of $row I want to copy the values of row into an entry of $result and not the references.

I have found a few solutions but they all seem rather awful.

$result[] = unserialize(serialize($row));
$result[] = array_flip(array_flip($row));

Both of the above work but seem like a lot of unnecessary and ugly code just to copy the contents of an array of references by value, instead of copying the references themselves.

Is there a cleaner way to accomplish this? If not what would the most efficient way be?

Thanks.

EDIT: As suggested below something such as:

function dereference($ref) {
    $dref = array();

    foreach ($ref as $key => $value) {
        $dref[$key] = $value;
    }

    return $dref;
}

$result[] = dereference($row);

Also works but seems equally as ugly.

This might be a duplicate, stackoverflow.com/questions/1190026/… — Anthony Forloney
– Anthony Forloney, Commented Mar 2, 2010 at 0:31
He is dealing with objects. I am dealing strictly with arrays. — anomareh
– anomareh, Commented Mar 2, 2010 at 1:19
What do you mean by "copy"? Which kind of "references" are you talking about that should be avoided? — Nico Haase
– Nico Haase, Commented Apr 30, 2020 at 15:40

Ross Snyder · Accepted Answer · 2010-03-02 01:49:10Z

4

Not sure I totally understand the question, but can you use recursion?

function array_copy($source) {
    $arr = array();

    foreach ($source as $element) {
        if (is_array($element)) {
            $arr[] = array_copy($element);
        } else {
            $arr[] = $element;
        }
    }

    return $arr;
}

$result = array();
$row = array(
    array('a', 'b', 'c'),
    array('d', 'e', 'f')
);

$result[] = array_copy($row);

$row[0][1] = 'x';

var_dump($result);
var_dump($row);

answered Mar 2, 2010 at 1:49

Ross Snyder

1,97511 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

anomareh Over a year ago

it appears as though your function would indeed work and what I suggested was incorrect.

Oliver · Accepted Answer · 2012-02-02 10:56:14Z

2

Extending the function above like follows solved a problem I had:

function array_copy($source) {
    $arr = array();

    foreach ($source as $element) {
        if (is_array($element)) {
            $arr[] = array_copy($element);
        } elseif (is_object($element)) {
            // make an object copy
            $arr[] = clone $element;
        } else {
            $arr[] = $element;
        }
    }
    return $arr;
}

answered Feb 2, 2012 at 10:56

Oliver

211 bronze badge

Comments

Modus Tollens · Accepted Answer · 2020-04-30 08:19:34Z

-1

$result = array_map(function($_){return $_;}, $row);

edited Apr 30, 2020 at 8:19

Modus Tollens

5,1343 gold badges41 silver badges47 bronze badges

answered Apr 30, 2020 at 8:11

DonJaime

1

2 Comments

Philipp Maurer Over a year ago

Hello DonJaime, welcome to StackOverflow. :-) You seem to have posted a nice answer here. Yet, instead of just posting code as an answer, please add an explanation to your solution, so the readers can also understand why it works.

Nico Haase Over a year ago

How is this different from $result = $row?

Collectives™ on Stack Overflow

PHP dereference array elements

3 Answers 3

1 Comment

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related