Convert non-nested and bracketed array to nested array

Question

I'm in PHP and I've got an array that looks like this. A single dimension array whose keys are bracketed strings.

array(
    'matrix[min_rows]' => '0',
    'matrix[max_rows]' => '',
    'matrix[col_order][]' => 'col_new_1',
    'matrix[cols][col_new_0][type]' => 'text',
    'matrix[cols][col_new_1][type]' => 'text',
    'matrix[cols][col_new_0][label]' => 'Cell 1',
    'matrix[cols][col_new_1][label]' => 'Cell 2',
    'matrix[cols][col_new_0][name]' => 'cell_1',
    'matrix[cols][col_new_1][name]' => 'cell_2',
    'matrix[cols][col_new_0][instructions]' => '',
    'matrix[cols][col_new_1][instructions]' => '',
    'matrix[cols][col_new_0][width]' => '33%',
    'matrix[cols][col_new_1][width]' => '',
    'matrix[cols][col_new_0][settings][maxl]' => '',
    'matrix[cols][col_new_0][settings][fmt]' => 'none',
    'matrix[cols][col_new_0][settings][content]' => 'all',
    'matrix[cols][col_new_1][settings][maxl]' => '140',
    'matrix[cols][col_new_1][settings][multiline]' => 'y',
    'matrix[cols][col_new_1][settings][fmt]' => 'none',
    'matrix[cols][col_new_1][settings][content]' => 'all',
)

Is there any easy way to convert that to a normal nested array, ie:

array(
    'matrix' => array(
        'min_rows' => '0',
        'max_rows' => '',
        'col_order' => array('col_new_1'),
        'cols' => array(
            'col_new_0' => array(
                'type' => 'text',
                'label' => 'Cell 1',
....etc....

This is my current solution, but I was wondering if there's something more native or efficient:

foreach ($decoded_field_type_settings as $key => $value)
{
    if (preg_match_all('/\[(.*?)\]/', $key, $matches))
    {
        $new_key = substr($key, 0, strpos($key, '['));

        if ( ! isset($field_type_settings[$new_key]))
        {
            $field_type_settings[$new_key] = array();
        }

        $array =& $field_type_settings[$new_key];

        $count = count($matches[1]) - 1;

        foreach ($matches[1] as $i => $sub_key)
        {
            if ( ! $sub_key)
            {
                if ($i < $count)
                {
                    $array[] = array();
                }
                else
                {
                    $array[] = $value;
                }
            }
            else
            {
                if ( ! isset($array[$sub_key]))
                {
                    if ($i < $count)
                    {
                        $array[$sub_key] = array();
                    }
                    else
                    {
                        $array[$sub_key] = $value;
                    }
                }
            }

            if ($i < $count)
            {
                $array =& $array[$sub_key];
            }
        }
    }
    else
    {
        $field_type_settings[$key] = $value;
    }
}

UPDATE: I posted an answer below.

It's a hidden form field that's populated by jQuery.serializeArray(). I'm piggybacking on a third party app, so I can't change this data. — Rob
– Rob, Commented Nov 17, 2011 at 22:00
I was just about to post an answer using http_build_query() and parse_str() but did a re-read of your question and discovered you already have this answer. The trouble is, you didn't post your solution as an Answer. Please edit your question to remove the solution, post your solution as an answer, and award it the green tick (this way your question is deemed resolved). ...oh, you haven't been on site for 6 years. — mickmackusa
– mickmackusa ♦, Commented Dec 21, 2017 at 14:46

Eric Petroelje · Accepted Answer · 2011-11-17 21:50:47Z

1

This might work, although it would probably generate some warnings:

$matrix = array();
foreach($arr as $key => $value) {
   eval('$' . $key . ' = \'' . $value . '\';');
}

var_dump($matrix);

answered Nov 17, 2011 at 21:50

Eric Petroelje

60.7k9 gold badges133 silver badges178 bronze badges

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4 Comments

Mathieu Dumoulin Over a year ago

I was about to propose that idea. Apart from doing a mega tokenizing job, this is the only valid idea i can think of.. Ugly, but works...

joshuahedlund Over a year ago

I thought of eval too, although I've generally heard you should avoid that for security purposes, etc... is that something to consider here? (Maybe you could at least make sure the string has no semicolons or $ signs or something...?)

Maxime Pacary Over a year ago

Problems may occur if the value stored in $value contains quotes, backslashes, dollar signs... Plus, running your solution gave a lot of 'undefined constant' notices.

Eric Petroelje Over a year ago

@Frosty - agreed, based my solution on the sample data he gave. And regarding the notices, that's why I mentioned that it would probably generate warnings

simshaun · Accepted Answer · 2011-11-17 22:22:19Z

I think this should do it...

<?php
function convert2dTo3d($source) {
    $refs = array();
    $output = array();

    foreach ($source AS $key => $val) {
        $tok = strtok($key, '[]');

        $prev_tok = NULL;
        while ($tok !== FALSE) {
            $this_ref =& $refs[$tok];

            if ($prev_tok === NULL)
                $output[$tok] =& $this_ref;
            else
                $refs[$prev_tok][$tok] =& $this_ref;

            $prev_tok = $tok;
            $tok = strtok('[]');

            if ($tok === FALSE)
                $refs[$prev_tok] = $val;
        }
    }

    return $output;
}


// Test
$source = array(
    'matrix[min_rows]' => '0',
    'matrix[max_rows]' => '',
    'matrix[col_order][]' => 'col_new_1',
    'matrix[cols][col_new_0][type]' => 'text',
    'matrix[cols][col_new_1][type]' => 'text',
    'matrix[cols][col_new_0][label]' => 'Cell 1',
    'matrix[cols][col_new_1][label]' => 'Cell 2',
    'matrix[cols][col_new_0][name]' => 'cell_1',
    'matrix[cols][col_new_1][name]' => 'cell_2',
    'matrix[cols][col_new_0][instructions]' => '',
    'matrix[cols][col_new_1][instructions]' => '',
    'matrix[cols][col_new_0][width]' => '33%',
    'matrix[cols][col_new_1][width]' => '',
    'matrix[cols][col_new_0][settings][maxl]' => '',
    'matrix[cols][col_new_0][settings][fmt]' => 'none',
    'matrix[cols][col_new_0][settings][content]' => 'all',
    'matrix[cols][col_new_1][settings][maxl]' => '140',
    'matrix[cols][col_new_1][settings][multiline]' => 'y',
    'matrix[cols][col_new_1][settings][fmt]' => 'none',
    'matrix[cols][col_new_1][settings][content]' => 'all',
);

echo "<pre>";
print_r(convert2dTo3d($source));
echo "</pre>";

Maxime Pacary · Accepted Answer · 2011-11-17 22:31:54Z

0

It seems that the OP wants, as output, an array declaration which can be parsed directly by PHP. So I suggest to use var_export().

$array = array(
    'matrix[min_rows]' => '0',
    // ......
    // ......
    // ......
    'matrix[cols][col_new_1][settings][content]' => 'all'
);

$matrix = array();

foreach ($array as $key => $value)
{
  // fix missing quotes around array indexes
  $key = str_replace(array("[", "]", "['']"), array("['", "']", "[]"), $key);
  // fill PHP array
  eval('$'.$key.' = $value;');
}

var_export($matrix);

edited Nov 17, 2011 at 22:31

answered Nov 17, 2011 at 22:13

Maxime Pacary

23.2k12 gold badges92 silver badges117 bronze badges

Comments

hakre · Accepted Answer · 2011-11-17 22:48:53Z

You can make use of a simple, regular expression based parser that creates a multidimensional array based on the information stored in the string per each key:

function parse_flat_matrix(array $flat)
{
    $matrix = array();
    $varname = 'matrix';
    $nameToken = '[a-z0-9_]*';

    foreach($flat as $key => $value)
    {
        $keys = preg_split(sprintf('/(\[%s\])/', $nameToken), $key, 0, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);

        if ($varname !== array_shift($keys))
        {
            throw new InvalidArgumentException(sprintf('Invalid key %s.', $key));
        }

        $p =& $matrix;
        foreach($keys as $k)
        {
            $r = preg_match(sprintf('/^\[(%s)\]$/', $nameToken), $k, $kk);
            if (!$r)
            {
                throw new InvalidArgumentException(sprintf('Invalid subkey %s in key %s.', $k, $key));
            }

            if ('' === $kk[1])
            {
                $p =& $p[];
            }
            else
            {
                $p =& $p[$kk[1]];
            }
        }
        $p = $value;
        unset($p);
    }

    return $matrix;
}

With your example data given, it will create this array:

Array
(
    [min_rows] => 0
    [max_rows] => 
    [col_order] => Array
        (
            [0] => col_new_1
        )

    [cols] => Array
        (
            [col_new_0] => Array
                (
                    [type] => text
                    [label] => Cell 1
                    [name] => cell_1
                    [instructions] => 
                    [width] => 33%
                    [settings] => Array
                        (
                            [maxl] => 
                            [fmt] => none
                            [content] => all
                        )

                )

            [col_new_1] => Array
                (
                    [type] => text
                    [label] => Cell 2
                    [name] => cell_2
                    [instructions] => 
                    [width] => 
                    [settings] => Array
                        (
                            [maxl] => 140
                            [multiline] => y
                            [fmt] => none
                            [content] => all
                        )

                )

        )

)

Rob · Accepted Answer · 2017-12-22 17:50:35Z

This was the simplest solution, involving no regex parsing:

$original_array = array(
    'matrix[min_rows]' => '0',
    'matrix[max_rows]' => '',
    'matrix[col_order][]' => 'col_new_1',
    'matrix[cols][col_new_0][type]' => 'text',
    'matrix[cols][col_new_1][type]' => 'text',
    'matrix[cols][col_new_0][label]' => 'Cell 1',
    'matrix[cols][col_new_1][label]' => 'Cell 2',
    'matrix[cols][col_new_0][name]' => 'cell_1',
    'matrix[cols][col_new_1][name]' => 'cell_2',
    'matrix[cols][col_new_0][instructions]' => '',
    'matrix[cols][col_new_1][instructions]' => '',
    'matrix[cols][col_new_0][width]' => '33%',
    'matrix[cols][col_new_1][width]' => '',
    'matrix[cols][col_new_0][settings][maxl]' => '',
    'matrix[cols][col_new_0][settings][fmt]' => 'none',
    'matrix[cols][col_new_0][settings][content]' => 'all',
    'matrix[cols][col_new_1][settings][maxl]' => '140',
    'matrix[cols][col_new_1][settings][multiline]' => 'y',
    'matrix[cols][col_new_1][settings][fmt]' => 'none',
    'matrix[cols][col_new_1][settings][content]' => 'all',
);

$query_string = http_build_query($original_array);

$final_array = array();

parse_str($query_string, $final_array);

var_dump($final_array);

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