How can I create multidimensional arrays from a string in PHP?

Question

So My problem is:

I want to create nested array from string as reference.
My String is "res[0]['links'][0]"
So I want to create array $res['0']['links']['0']

I tried:

$result = "res[0]['links'][0]";
$$result = array("id"=>'1',"class"=>'3');
$result = "res[0]['links'][1]";
$$result = array("id"=>'3',"class"=>'9');

when print_r($res) I see:

<b>Notice</b>:  Undefined variable: res in <b>/home/fanbase/domains/fanbase.sportbase.pl/public_html/index.php</b> on line <b>45</b>

I need to see:

Array
(
    [0] => Array
        (
            [links] => Array
                (
                    [0] => Array
                        (
                            [id] => 1
                            [class] => 3
                        )

                )

        )
    [1] => Array
        (
            [links] => Array
                (
                    [0] => Array
                        (
                            [id] => 3
                            [class] => 9
                        )

                )

        )

)

Thanks for any help.

Why do you want to create an array from a string? Maybe it would be better to explain what you're trying to do at a high level, since its probable someone can suggest a better way of doing it (i.e. one that doesn't cause you to have an array in a string) — lll
– lll, Commented Feb 7, 2011 at 11:09
Those strings aren't even consistent with what you want in your array: surely the second $result should be "res[1]['links'][0]" instead of $result = "res[0]['links'][1]" — Mark Baker
– Mark Baker, Commented Feb 7, 2011 at 11:16

mario · Accepted Answer · 2011-02-07 11:31:45Z

1

So you have a description of an array structure, and something to fill it with. That's doable with something like:

function array_create(&$target, $desc, $fill) {

    preg_match_all("/[^\[\]']+/", $desc, $uu);
       // unoptimized, always uses strings

    foreach ($uu[0] as $sub) {
        if (! isset($target[$sub])) {
             $target[$sub] = array();
        }
        $target = & $target[$sub];
    }
    $target = $fill;
}

array_create( $res, "[0]['links'][0]", array("id"=>'1',"class"=>'3') );
array_create( $res, "[0]['links'][1]", array("id"=>'3',"class"=>'9') );

Note how the array name itself is not part of the structure descriptor. But you could theoretically keep it. Instead call the array_create() function with a $tmp variable, and afterwards extract() it to achieve the desired effect:

array_create($tmp, "res[0][links][0]", array(1,2,3,4,5));
extract($tmp);

Another lazy solution would be to use str_parse after a loop combining the array description with the data array as URL-encoded string.

edited Feb 7, 2011 at 11:31

answered Feb 7, 2011 at 11:22

mario

146k20 gold badges243 silver badges293 bronze badges

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

1 Comment

Deele Over a year ago

Nice! I added my example of use, in another answer to this question.

Ankur · Accepted Answer · 2011-02-07 12:21:36Z

1

I have a very stupid way for this, you can try this :-) Suppose your string is "res[0]['links'][0]" first append $ in this and then put in eval command and it will really rock you. Follow the following example

$tmp = '$'.'res[0]['links'][0]'.'= array()';

eval($tmp);

Now you can use your array $res

100% work around and :-)

`

answered Feb 7, 2011 at 12:21

Ankur

1118 bronze badges

1 Comment

mario Over a year ago

Well yes, that borders on being bad. It's only ever acceptable if such constructs originate from configuration files etc. Application input -even if meticulously filterd- should never be in there even partial. However still one of the few valid eval uses. +1

helle · Accepted Answer · 2011-02-07 11:16:27Z

0

$res = array();
$res[0]['links'][0] = array("id"=>'1',"class"=>'3');
$res[0]['links'][0] = array("id"=>'3',"class"=>'9');

print_r($res);

but read the comments first and learn about arrays first.

answered Feb 7, 2011 at 11:16

helle

11.8k9 gold badges58 silver badges86 bronze badges

Comments

Deele · Accepted Answer · 2012-06-20 11:54:00Z

In addition to mario's answer, I used another function from php.net comments, together, to make input array (output from jquery form serializeArray) like this:

[2] => Array
    (
        [name] => apple[color]
        [value] => red
    )

[3] => Array
    (
        [name] => appleSeeds[27][genome]
        [value] => 201
    )

[4] => Array
    (
        [name] => appleSeeds[27][age]
        [value] => 2 weeks
    )

[5] => Array
    (
        [name] => apple[age]
        [value] => 3 weeks
    )

[6] => Array
    (
        [name] => appleSeeds[29][genome]
        [value] => 103
    )

[7] => Array
    (
        [name] => appleSeeds[29][age]
        [value] => 2.2 weeks
    )

into

Array
(
    [apple] => Array
        (
            [color] => red
            [age] => 3 weeks
        )
    [appleSeeds] => Array
        (
            [27] => Array
                (
                    [genome] => 201
                    [age] => 2 weeks
                )
            [29] => Array
                (
                    [genome] => 103
                    [age] => 2.2 weeks
                )
        )
)

This allowed to maintain numeric keys, without incremental appending of array_merge. So, I used sequence like this:

function MergeArrays($Arr1, $Arr2) {
    foreach($Arr2 as $key => $Value) {
        if(array_key_exists($key, $Arr1) && is_array($Value)) {
              $Arr1[$key] = MergeArrays($Arr1[$key], $Arr2[$key]);
        }
        else { $Arr1[$key] = $Value; }
    }
    return $Arr1;
}
function array_create(&$target, $desc, $fill) {
    preg_match_all("/[^\[\]']+/", $desc, $uu);
    foreach ($uu[0] as $sub) {
        if (! isset($target[$sub])) {
              $target[$sub] = array();
        }
        $target = & $target[$sub];
    }
    $target = $fill;
}
$input = $_POST['formData'];
$result = array();
foreach ($input as $k => $v) {
    $sub = array();
    array_create($sub, $v['name'], $v['value']);
    $result = MergeArrays($result, $sub);
}

Collectives™ on Stack Overflow

How can I create multidimensional arrays from a string in PHP?

4 Answers 4

1 Comment

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

1 Comment

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related