Remove elements from recursive array from bottom to top in PHP

Question

Given the following array:

array(
    0 => array(
        0 => 56,
        1 => array(
            0 => 57,
            1 => 58,
            2 => 59,
        ),
        2 => 60
    ),
    1 => array(
        0 => 61,
        1 => array(
            0 => 62,
            1 => array(
                0 => 63,
                1 => 64
            )
        )
    )
)

How could I proceed to remove elements from that array starting from deepest elements? My elements are ID in a database and key constraints make me unable to delete parents if they have children...

I looked for something using RecursiveIterator but no solution so far...

EDIT

Actually, no need to get a specific algo, a standard recursion will do the job

You need to traverse the array from the deepest element to the parent element to delete the records from Database. right? — Hari
– Hari, Commented Apr 28, 2017 at 12:04
Yes, but I can achieve this from parents to children: if my parent has children, go through the children and delete. Then recheck if it still has children. If no, delete it and go on — VeZoul
– VeZoul, Commented Apr 28, 2017 at 12:06
Can you explain little bit more. you need the Ids in the form of 56, 57, 58 ...? — Hari
– Hari, Commented Apr 28, 2017 at 12:20
I need to remove first 57, 58, 59, then, 56, then 60, then 63, 64, then 62, then 61 — VeZoul
– VeZoul, Commented Apr 28, 2017 at 12:22

sevavietl · Accepted Answer · 2017-04-28 12:43:43Z

2

You can visit leaves only with RecursiveIteratorIterator and RecursiveIteratorIterator::LEAVES_ONLY mode and then reverse the resulting array:

$iterator = new RecursiveIteratorIterator(
    new RecursiveArrayIterator($ids),
    RecursiveIteratorIterator::LEAVES_ONLY
);

$ids = [];

foreach ($iterator as $id) {
    // You can put elements directly in the beggining of an array
    // or reverse array later.
    // array_unshift($ids, $id);
    $ids[] = $id;
}

$ids = array_reverse($ids);

Here is working demo.

answered Apr 28, 2017 at 12:43

sevavietl

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1 Comment

VeZoul Over a year ago

That's it! Great! Thank you!

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