Multidimensional array to a nested multidimensional array in PHP

Question

I have an array like so:

   sid         sname               did               dname
    1         Basketball            1                 Mini
    1         Basketball            3                 Cadet
    2         Baseball              8             Little League
    2         Baseball              6             Junior League
    1         Basketball            5                Masters

I was trying to get this and transform it to a nested array like so:

 array('Basketball' => array(
                        'id' => 1, 
                        'divisions' => array(
                                          1 => 'Mini',
                                          3 => 'Cadet',
                                          5 => 'Masters'
                                       )
                       ),
       'Baseball' => array(
                        'id' => 2, 
                        'divisions' => array(
                                          8 => 'Little League',
                                          6 => 'Junior League'
                                       )
                       )
 );

And I am using this foreach loop which is not working, it replaces each division entry so I'm left with only one division entry which is the last entry.

$result = '';
foreach($row as $r) 
{

     $result[$r['sname']] = array('id' => $r['sid'], 'divisions' => array($r['did'] => $r['dname']));

}

This foreach loop gives me this result:

 array('Basketball' => array(
                        'id' => 1, 
                        'divisions' => array(
                                          5 => 'Masters'
                                       )
                       ),
       'Baseball' => array(
                        'id' => 2, 
                        'divisions' => array(
                                          6 => 'Junior League'
                                       )
                       )
 );

I don't understand what is wrong here.. can anybody help me out here?

Ewan Todd · Accepted Answer · 2009-12-12 17:23:53Z

3

The problem is that you redefine $result[$r['sname']] each time. You only need to define it if it is not already defined.

$result = array(); // initialize this to an appropriate type!
foreach($row as $r) 
{

   if(!isset($result[$r['sname']]))
   {
      $result[$r['sname']] = array('id' => $r['sid'], 'divisions' => array($r['did'] => $r['dname']));
      continue;
   }
   $result[$r['sname']]['divisions'][$r['did']] = $r['dname'];

}

edited Dec 12, 2009 at 17:23

answered Dec 12, 2009 at 16:54

Ewan Todd

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Comments

just somebody · Accepted Answer · 2009-12-12 16:53:52Z

1

$result = array();
foreach($row as $r) 
{

     $result[$r['sname']]['id'] = $r['sid'];
     $result[$r['sname']]['divisions'][$r['did']] = $r['dname'];

}

answered Dec 12, 2009 at 16:53

just somebody

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1 Comment

Ewan Todd Over a year ago

+1 Assuming it works, this is a pretty elegant read. Of course it re-initializes the 'id' value each time, but that's not so expensive.

Matěj G. · Accepted Answer · 2009-12-12 16:49:09Z

0

Check for existence of the key with isset() or array_key_exists() beforehand so that it doesn't get rewritten.

answered Dec 12, 2009 at 16:49

Matěj G.

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Comments

Scott Evernden · Accepted Answer · 2009-12-12 16:51:37Z

0

i think you want:

$result[$r['sname']][] = array('id' => $r['sid'], 'divisions' => array($r['did'] => $r['dname']));

answered Dec 12, 2009 at 16:51

Scott Evernden

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Comments

Matt Ellen · Accepted Answer · 2009-12-12 17:03:27Z

0

$result = array();
foreach($row as $r) 
{
    if(isset($result[$r['sname']]))
    {
        array_push($result[$r['sname']], array('id' => $r['sid'], 'divisions' => array($r['did'] => $r['dname'])));
    }
    else
    {
        $result[$r['sname']] = array('id' => $r['sid'], 'divisions' => array($r['did'] => $r['dname']))
    }
}

What you are currently doing is overwriting the entry for $result[$r['sname']], so it will only ever have one array in it.

I use the if because $array[] = is quicker than array_push see php docs

answered Dec 12, 2009 at 17:03

Matt Ellen

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