PHP RecursiveArrayIterator class get key-value pair recursive

Question

I tried to wrote a custom array iterator with PHP's factory class. My problem: I need all array's all datas, example, here is a simple PHP array:

Array
(
    [authentication] => Array
        (
            [basic] => Array
                (
                    [username] => guest
                    [password] => guest
                )

            [filters] => Array
                (
                    [price] => 100
                    [owener] => me
                )

        )

)

I see on PHP's doc page, I can use two simple class and iterate with simple foreach:

    $iterator = new \RecursiveIteratorIterator(new \RecursiveArrayIterator($this->phpArray));
    foreach($iterator as $key => $value) {
        $d = $iterator->getDepth();
        echo "depth: $d $key => $value\n";
    }

This program throw following output:

depth: 2 key: username, value: guest
depth: 2 key: password, value: guest
depth: 2 key: price, value: 100
depth: 2 key: owener, value: me

How to modify my code what can do a following example output with all datas:

depth: 0 key: authentication, value:
depth: 1 key: basic, value:
depth: 1 key: filters, 
depth: 2 key: username, value: guest
depth: 2 key: password, value: guest
depth: 2 key: price, value: 100
depth: 2 key: owener, value: me

Thank you!

sevavietl · Accepted Answer · 2016-12-25 10:00:23Z

6

When you use RecursiveIteratorIterator you can set different modes of traversing. The default one is RecursiveIteratorIterator::LEAVES_ONLY. That's why you get only leaves, but not all values (by the way array_walk_recursive has the same behavior). To visit all elements you need to set the mode to RecursiveIteratorIterator::SELF_FIRST:

$iterator = new \RecursiveIteratorIterator(
    new \RecursiveArrayIterator($array),
    \RecursiveIteratorIterator::SELF_FIRST
);

Here is working demo.

answered Dec 25, 2016 at 10:00

sevavietl

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1 Comment

sevavietl Over a year ago

@Gábor, you are welcome. Iterators indeed badly documented, and it is hard to get it right.

Rajdeep Paul · Accepted Answer · 2016-12-25 00:33:13Z

Alternatively, you could use a recursive function like this:

function traverseArray($arr, &$depthArray, $depth = 0){
    foreach($arr as $key => $value){
        if(is_array($value)){
            $depthArray[$depth][] = array('depth' => $depth, 'key' => $key, 'value' => '');
            traverseArray($value, $depthArray, ++$depth);
            --$depth;
        }else{
            $depthArray[$depth][] = array('depth' => $depth, 'key' => $key, 'value' => $value);
        }
    }
}

Create an empty array named $depthArray and call this function with two arguments, first one would be your original array $this->phpArray and second one would be this $depthArray, like this:

$depthArray = array();
traverseArray($this->phpArray, $depthArray);

Finally, use nested foreach loops to traverse $depthArray and display key, value and the associated depth of that element, like this:

foreach($depthArray as $depth => $arr){
    foreach($arr as $a){
        echo 'depth:' . $a['depth'] . ' key: ' . $a['key'] . ' value: ' . $a['value'] . '<br />';
    }
}

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