Echo a multidimensional array in PHP

Question 1

I have a multidimensional array and I'm trying to find out how to simply "echo" the elements of the array. The depth of the array is not known, so it could be deeply nested.

In the case of the array below, the right order to echo would be:

This is a parent comment
This is a child comment
This is the 2nd child comment
This is another parent comment

This is the array I was talking about:

Array
(
    [0] => Array
        (
            [comment_id] => 1
            [comment_content] => This is a parent comment
            [child] => Array
                (
                    [0] => Array
                        (
                            [comment_id] => 3
                            [comment_content] => This is a child comment
                            [child] => Array
                                (
                                    [0] => Array
                                        (
                                            [comment_id] => 4
                                            [comment_content] => This is the 2nd child comment
                                            [child] => Array
                                                (
                                                )
                                        )
                                )
                        )
                )
        )

    [1] => Array
        (
            [comment_id] => 2
            [comment_content] => This is another parent comment
            [child] => Array
                (
                )
        )
)

Question 2

It looks like you're only trying to write one important value from each array. Try a recursive function like so:

function RecursiveWrite($array) {
    foreach ($array as $vals) {
        echo $vals['comment_content'] . "n";
        RecursiveWrite($vals['child']);
    }
}

You could also make it a little more dynamic and have the 'comment_content' and 'child' strings passed into the function as parameters (and continue passing them in the recursive call).

Question 3

You need to iterate over your results, adding a new entry to the output when you encounter a new team, or updating the points value when you find the same team again. This is most easily done by initially indexing the output by the team name, and then using array_values to re-index the array numerically:

$teams = array();
foreach ($results as $result) {
    $team = $result['team'];
    if (!isset($teams[$team])) {
        $teams[$team] = array('team' => $team, 'points' => $result['punti']);
    }
    else {
        $teams[$team]['points'] += $result['punti'];
    }
}
$teams = array_values($teams);
print_r($teams);

Output (for your sample data):

Array
(
    [0] => Array
        (
            [team] => Red Bull Racing
            [points] => 418
        )
    [1] => Array
        (
            [team] => Scuderia Ferrari
            [points] => 353
        )
    [2] => Array
        (
            [team] => Mercedes-AMG
            [points] => 516
        )
    [3] => Array
        (
            [team] => Racing Point F1
            [points] => 147
        )
    [4] => Array
        (
            [team] => Haas F1
            [points] => 127
        )
)

Demo on 3v4l.org

Question 4

Try this:

function getLastId(&$array){
    $tmp=end($array);
    return $tmp['id'];
}

Question 5

No, it's not possible. Ordering means that you can compare two elements and determine which order they should have. Your query fails at that when you have two 1 elements.

However, that doesn't mean that it can't be done algorithmically, only that sorting or ordering is not the right tool for the job.

Question 6

You can do it like this, do the calculation from the innermost of the array. Check the demo.

<?php
function f(&$array)
{
    foreach($array as $k => &$v)
    {
        if(is_array($v))
        {
            if(count($v) == count($v, 1))
            {
                unset($array[$k]);
                if($k == 'sum')
                {
                    $v =  array_sum($v);
                    $array[] = $v;

                }elseif($k == 'multiply'){
                    $v = array_product($v);
                    $array[] = $v;
                }else{

                    foreach($v as $vv)
                        $array[] = $vv;
                }
            }else
                f($v);
        }
    }
}

while(count($array) != count($array, 1))
{
    f($array);
}

print_r($array);

Note：

traverse array from outer to inner
traverse array from inner to outer

Echo a multidimensional array in PHP

Answers

php,arrays,multidimensional-array,nested