How to modify certain Array keys with RecursiveIteratorIterator

Question

I have a multi-level Array. Number of levels (sub-arrays) isn't known. It could be only two, but also could be 5. The only thing I know - there are certain (known) keys on each level.

Let consider following example:

Array
(
    [number] => 21
    [otherkey] => value
    [sub] => Array
        (
            [count] => 
            [number] => 29
            [some] => thing
            [range] => Array
                (
                   ...
                )

            [sub] => Array
                (
                    [count] => 1
                    [number] => 16
                    [key] => value
                    [date] => 2013-07-25
                    [sub] => Array
                        (
                            [count] => 0
                            [number] => 4
                            [key] => value
                            [sub] => Array
                                (
                                    [count] => 1
                                    [number] => 24
                                    [key] => value
                                    [sub] => last
                                )

                        )

                )

        )

)

My goal is to iterate through all 'number' keys and create text like 'even' or 'odd', but the result should be saved under own key (say number_str) on each level

So modified Array should look like this:

 Array
    (
        [number] => 21
        [otherkey] => value
        [sub] => Array
            (
                [count] => 
                [number] => 29
                [some] => thing
                [range] => Array
                    (
                     ...
                    )
                [sub] => Array
                    (
                        [count] => 1
                        [number] => 16
                        [key] => value
                        [date] => 2013-07-25
                        [sub] => Array
                            (
                                [count] => 0
                                [number] => 4
                                [key] => value
                                [sub] => Array
                                    (
                                        [count] => 1
                                        [number] => 24
                                        [key] => value
                                        [sub] => last
                                        [number_str] => even //new key
                                    )
                                [number_str] => even //new key

                            )
                        [number_str] => even //new key

                    )
                [number_str] => odd //new key

            )
        [number_str] => odd //new key
    )

So I tried to use RecursiveIteratorIterator

$rai = new RecursiveArrayIterator($data);
$rii = new RecursiveIteratorIterator($rai);

foreach ($rii as $idx => $level) {
    if($idx === 'number')
    {
        $str = ($level % 2) ? 'odd' : 'even';
        $rii->offsetSet('number_str', $str);
    }
}

but it didn't worked. So I found kind of 'workaround'. It seems to do, what I expect if each Sub-Array is an Object of stdClass

convert the original Array (and all sub-array) to a stdClass

$data = json_encode(json_decode($data)); // ..dirty gimmick. Possible performance killer ?

$rai = new RecursiveArrayIterator($data);
$rii = new RecursiveIteratorIterator($rai);

foreach ($rii as $idx => $level) {
    //same logic as above...
}

var_dump($rai);

now it looks like I have wished results, the only problem is, all sub-level now are instances of stdClass

code online -> http://ideone.com/PIiZOX

QUESTION Is there a way to get the same results, but without the gimmick with json_decode/json_encode so the output will be a normal Array ?

P.S : I know, there is array_walk() but it's not an option

UPDATE: I should mention that the question is not about getting correct results. I know, that custom recursiv function (and maybe array_walk_recursive()) will do the trick. Its more about SPLs RecursiveIterators as possible solutuion. I just wonder myself, why it does work with strClasses and why don't with regular Array.

The example Array from obeve isn't real use-case. As you may guess, the real use-case are Arrays (sometimes more than 600 rows) with data from DB. Some of them have sub-arrays. The only thing i know are keys which should be modified (by a given rule). Performance is a main criteria

Expedito · Accepted Answer · 2013-07-25 20:08:16Z

1

function even_or_odd(&$arr){
    if(is_array($arr)){
        if (isset($arr['number'])){
            if ($arr['number']%2 == 1){
                $arr['number_str'] = 'odd';
            } else {
                $arr['number_str'] = 'even';
            }
        }
        foreach( $arr as $key => &$val ){
            if(is_array($val)){
                self::even_or_odd($val);
            }
        }
    }
}

answered Jul 25, 2013 at 20:08

Expedito

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Comments

chris-l · Accepted Answer · 2013-07-25 20:13:06Z

1

Try with a custom recursive function:

function addEvenOrOdd(&$array) {
    $array['number_str'] = ($array['number'] % 2) ? 'odd' : 'even';
    ksort($array);
    if(isset($array['sub']) && is_array($array['sub'])) {
        addEvenOrOdd($array['sub']);
    }
}
addEvenOrOdd($yourarray);

See it working live here: http://codepad.viper-7.com/vBc42b

edited Jul 25, 2013 at 20:13

answered Jul 25, 2013 at 19:59

chris-l

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Павел Осипов · Accepted Answer · 2013-07-25 20:24:27Z

1

I think it's not need to use RecursiveArrayIterator, simple recursive function will be enough. Hope this will helps:

function iterate_recursive( &$target_arr ){
    $val = 'odd';
    if( $target_arr[ 'number' ] % 2 == 0 ){
        $val = 'even';
    }
    $target_arr[ 'number_str' ] = $val;

    if( array_key_exists( 'sub', $target_arr ) and is_array($target_arr['sub'])){
        iterate_recursive( $target_arr[ 'sub' ] );
    }
}

$dta_arr = Array
    (
    'number' => 21,
    'otherkey' => 'value',
    'sub' => Array
        (
        'count' => 123,
        'number' => 29,
        'some' => 'thing',
        'range' => Array
            (
            'stub' => False,
        ),
        'sub' => Array
            (
            'count' => 1,
            'number' => 16,
            'key' => 'value',
            'date' => 2013 - 07 - 25,
            'sub' => Array
                (
                'count' => 0,
                'number' => 4,
                'key' => 'value',
                'sub' => Array
                    (
                    'count' => 1,
                    'number' => 24,
                    'key' => 'value',
                    'sub' => 'thing',
                )
            ),
        ),
    ),
);


iterate_recursive( $dta_arr );
print_r($dta_arr);

edited Jul 25, 2013 at 20:24

answered Jul 25, 2013 at 20:00

Павел Осипов

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2 Comments

Павел Осипов Over a year ago

Take a look here: php.net/manual/en/class.recursiveiteratoriterator.php Here is some benchmark in comments, comparing iterations and simple recursive function realization, if speed is most important for you, when recursive functions are more quick than iterators.

Павел Осипов Over a year ago

Also, by default RecursiveIteratorIterator returns flattered array, and if nesting levels order is important for you, when you will need to use $iterator->getArrayCopy() method, what will return multilevel array, but will double amount of memory used to store both arrays, and also will add time delay to proceed it

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