Simple recursive tree in PHP / MySQL

问题:

I have this table in MySQL:

id       name            mother
1        grandma         0
2        myuncle         1
3        mymom           1
4        me              3
5        mysister        3
6        myson           4
7        new_grandma_son 1

I almacenate this info in an array called data[]

$data=array(
        array("id"=>1,"name"=>"grandma",        "mother"=>0),
        array("id"=>2,"name"=>"myuncle",        "mother"=>1),
        array("id"=>3,"name"=>"mymom",          "mother"=>1),
        array("id"=>4,"name"=>"me",             "mother"=>3),
        array("id"=>5,"name"=>"mysister",       "mother"=>3),
        array("id"=>6,"name"=>"myson",          "mother"=>4),
        array("id"=>7,"name"=>"new_grandma_son","mother"=>1)
    );

And for make a family tree I am using this recursive function:

function tree($data, $mom = 0, $level = 0){
     foreach ($data as $row){
          if ($row['mother'] == $mom) {
               echo str_repeat("-", $level).$row['name']."<br>";
               tree($data, $row['id'], $level);
          }
          else $level++;
     }
}

When I call the function tree($data); it shows this:

grandma
-myuncle (level 1)
-mymom
----me (level 4??)
---------myson (level 9??)
----mysister
----new_grandma_son (level 4??)

I have the mistake in the else $level++;, because is adding levels when $row['mother'] != $mom, going through all the rows, but I don't know how to make it. Anyone knows? Thank you.

Solution (By Frits van Campen):

               tree($data, $row['id'], $level+1);

          // (eliminate this else $level++; )

Thanks!

回答1:

function tree($data,$mom=0,$level=0){
     foreach($data as $row){
          if($row['mother']==$mom){
               echo str_repeat("-",$level).$row['name']."<br>";
               tree($data,$row['id'],$level+1);
          }
     }
}

I think this fixes your code. Can you supply the $data so I can test it?

回答2:

You may try like this, which returns value in a Array format. I used this function for Item category Tree,

    function categoryDropDown($categoryArray, $parentId, $level, $options)
{   
    $level++;
    foreach ($categoryArray  as  $array)
    {
        if($array['parentId'] == $parentId)
        {
            $opt = str_repeat(">> ", $level-1) . $array['name'] ;         
            $options[$array['id']] =  $opt;
            $newParent = $array['id'];              
            $options = categoryDropDown($categoryArray, $newParent, $level , $options);         
        }
    }   
    return $options;    
}

----output----

//Array Key contains category Id.


Array
(
    [1] => Electronics
    [2] => >> Mobile
    [5] => >> >> Mobile Accessories
    [7] => >> >> >> Sub Category 1
    [9] => >> >> >> Sub Category 3
    [3] => >> Laptop
    [6] => >> >> Laptop Accessories
    [8] => >> >> >> Sub Category 2
    [10] => >> >> >> Sub Category 4
    [4] => >> Tablet
    [11] => Main Category 2
)

You can refer some advance version of this code at here How to display select multiple drop down from using array in php?

回答3:

Cant you just replace the str_repeat("-", $level) with str_repeat("-", $row['mother'])?

Or maybe in your case str_repeat("-", $row['mother'] - 1) as you don't want to start with a - in front of grandma.