Get with PHP Array Tree Values Recursively with start and stop limit level

Question

I am making a module for creating navigation menus and I would like to give the possibility to set an initial and final level. I have this array tree with level how can return it setting a start level and stop level ? this is my function that return empty.

Original Array:

Array
(
    [0] => Array
        (
            [id] => 22
            [pid] => 12
            [level] => 0
            [children] => 
        )

    [1] => Array
        (
            [id] => 24
            [pid] => 12
            [level] => 0
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 27
                            [pid] => 24
                            [level] => 1
                            [children] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 28
                                            [pid] => 27
                                            [level] => 2
                                            [children] => 
                                        )

                                )

                        )

                )

        )

    [2] => Array
        (
            [id] => 25
            [pid] => 12
            [level] => 0
            [children] => 
        )

    [3] => Array
        (
            [id] => 26
            [pid] => 12
            [level] => 0
            [children] => 
        )

)

My function:

function get_tree_limit ($pages, $start_level, $stop_level) {

    $result = Array();

    foreach( $pages as $page ) {

        $children = Array();

        if(isset($page['children'])){
            $children = get_tree_limit ($page['children'], $start_level, $stop_level);
        }

        if($page['level'] >= $start_level && $page['level'] <= $stop_level){

            $result[] = Array(
                'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'],
                'children' => $children
            );

        }

    }

    return $result;

}

if I try:

$rpage = get_tree_limit ($pages, 1, 2);
print_r($rpage);

The result is empty:

Array()

Where I am wrong ?

Thanks.

The problem is that at level 0, although you set $children - you never add this anywhere to be returned. — Nigel Ren
– Nigel Ren, Commented Nov 30, 2019 at 12:50
@NigelRen that should return the array empty if no children. If I remove the condition start and stop level return correct. But of coarse my concept is wrong or I solved my self. Can you write the correct fuction or difficult to understand. Thanks. — Daebak
– Daebak, Commented Nov 30, 2019 at 13:02
@ShringirajDewangan $pages of coarse is the original array you can see at the top of the post. — Daebak
– Daebak, Commented Nov 30, 2019 at 13:09
Scope of $result variable is in function only and return value is only for key 0 and your start level is 1 — Shringiraj Dewangan
– Shringiraj Dewangan, Commented Nov 30, 2019 at 15:36

Aksen P · Accepted Answer · 2019-11-30 23:49:19Z

1

During simple foreach loop you need to check the main index children and in case of it has array datatype you need to turn on recursive action (use is_array($page['children'])):

if(is_array($page['children'])){ } else {  }

In case of non-array you can just append this values to the result array if the level is in range:

if(   $page['level'] >= $start_level 
   && $page['level'] <= $stop_level 
   && is_numeric($page['level'])
  ){
     $result[$ind] = Array(
                        'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'], 
                        'children' => $page['children']
     ); 
}

In case of array datatype you need to do the same, but with recursive action:

if(  $page['level'] >= $start_level 
  && $page['level'] <= $stop_level 
  && is_numeric($page['level'])){ 

  $result[$ind] = Array(
                        'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'], 
                        'children' => @get_tree_limit($page, $start_level, $stop_level)['children'] 
  );   
}

if (!isset($result[$ind]) ) {
    if (@count(get_tree_limit($page, $start_level, $stop_level)['children'])>0){
        $result[$ind] = @get_tree_limit($page, $start_level, $stop_level)['children'];
    }
}

@ hides warnings, so the result body of the function looks like next:

$result = Array();

foreach($pages as $ind => $page ) {

        if(is_array($page['children'])){ 

           if($page['level'] >= $start_level 
           && $page['level'] <= $stop_level 
           && is_numeric($page['level'])){ 
                //print_r($page);
                $result[$ind] = Array(
                    'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'], 
                    'children' => @get_tree_limit($page, $start_level, $stop_level)['children'] 
                );   
            }

            if (!isset($result[$ind]) ) {
               if (@count(get_tree_limit($page, $start_level, $stop_level)['children'])>0){
                    $result[$ind] = @get_tree_limit($page, $start_level, $stop_level)['children'];
               }
            } 

        } else {
            if($page['level'] >= $start_level && $page['level'] <= $stop_level && is_numeric($page['level'])){
                $result[$ind] = Array(
                    'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'], 
                    'children' => $page['children']
                ); 
            } 
        } 
}

return $result;

For example, $res = get_tree_limit($ar, 2, 3); returns only 2 and 3 levels of the tree:

Array
(
    [0] => Array
        (
            [id] => 28
            [pid] => 27
            [level] => 2
            [children] => Array
                (
                    [id] => 29
                    [pid] => 28
                    [level] => 3
                    [children] => 2
                )

        )

)

Demo

You can choose any level range and you'll get correspond tree branch.

answered Nov 30, 2019 at 23:49

Aksen P

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17 Comments

Daebak Over a year ago

Your code does its job and looks very clean. Compliments! I've always said that programmers should write code and avoid words :) Thanks

Daebak Over a year ago

testing your code I check that there is a small problem. if Start or Stop limit is 0 should be ignored. What I mean if you set start_level = 2 and stop_level = 0 should show level 2, 3. same start level 0 stop level 2 should show level 0,1,2. is start_level=0 and stop_level=0 should to show 0,1,2,3.

Aksen P Over a year ago

@DaebakDo, no, it works as a range - you can choose from level to level. 0-0 - gives 0 levels, 0-1 - gives first 2, 1-2 - gives 1 and 2

Aksen P Over a year ago

If you wanna I can fix this with your wishes.

Daebak Over a year ago

thanks you are really kind. By the way if children doesn't exist return error. For this my code was so long :D

|

Daebak · Accepted Answer · 2019-11-30 21:40:22Z

0

Ok this function does its job and I insert if someone is looking for it and to receive some suggestions. I also added the control in the case start and stop are null.

function get_tree_limit ($pages, $start_level, $stop_level) {

    $result = Array();

    foreach($pages as $page) {

        $children = Array();

        if(isset($page['children'])){
            $children = get_tree_limit ($page['children'], $start_level, $stop_level);
        }

        if($start_level > 0 && $stop_level > 0){

            if(!empty($children)){

                if($page['level'] >= $start_level && $page['level'] <= $stop_level){

                    $result[] = Array(
                        'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'], 'children' => $children
                    );

                } else {

                    $result = $children;

                }

            } else {

                if($page['level'] >= $start_level && $page['level'] <= $stop_level){

                    $result[] = Array(
                        'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level']
                    );

                }

            }

        } elseif($start_level <= 0 && $stop_level > 0) {

            if(!empty($children)){

                if($page['level'] <= $stop_level){

                    $result[] = Array(
                        'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'], 'children' => $children
                    );

                } else {

                    $result = $children;

                }

            } else {

                if($page['level'] <= $stop_level){

                    $result[] = Array(
                        'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level']
                    );

                }

            }

        } elseif($start_level > 0 && $stop_level <= 0) {

            if(!empty($children)){

                if($page['level'] >= $start_level){

                    $result[] = Array(
                        'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'], 'children' => $children
                    );

                } else {

                    $result = $children;

                }

            } else {

                if($page['level'] >= $start_level){

                    $result[] = Array(
                        'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level']
                    );

                }

            }

        } else {

            if(!empty($children)){

                $result[] = Array(
                    'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level'], 'children' => $children
                );

            } else {

                $result[] = Array(
                    'id' => $page['id'], 'pid' => $page['pid'], 'level' => $page['level']
                );              

            }

        }

    }

    return $result;

}

test

http://sandbox.onlinephpfunctions.com/code/4e9b1822d294f0af65f81a8ad9ce5f61db7e43f7

edited Nov 30, 2019 at 21:40

answered Nov 30, 2019 at 19:52

Daebak

4192 silver badges9 bronze badges

5 Comments

Aksen P Over a year ago

It doesn't works

Daebak Over a year ago

why if I pass the array and debug all the ase return me the correct array.

Daebak Over a year ago

@AksenP you can test here sandbox.onlinephpfunctions.com/code/…

Aksen P Over a year ago

And what? 0 to 0 gives 0 to 2 :D You're failed.

Daebak Over a year ago

@AksenP Change it

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