Multi-Dimensional Arrays Help - And Other Questions on Arrays

[Dormilich]

Kind of like sayins that each cell can have an array inside of it and it just keeps going from there.

that's the crucial point.

[Dormilich]

If I wanted to have a strict set of rules, would I just use E_ALL?

yup.

(blablablubb…20 character limit exeeded…narf)

[Ciary]

take a look at this: its a visual example of a 4D array. hope this helps.

and indeed you create it by putting an array in a array. and that one in another array and that one in another and ... (you get the poin :) )

[fjm]

that's the crucial point.

Scary thought because each cell or array can have an infinite number of arrays. It blows my mind to even imagine it.

Ok, so if I can just bring this into perspective and maybe have you guys guide me a bit now that I can visualize it. Let's say I have an array like this:

array
(
  array
  (
    'mykey0' => 'myvalue0',
    'mykey1' => 'myvalue1',
    'mykey2' => 'myvalue2'
  ),
  array
  (
    '0' => 'somthin',
    '1' => 'somthin',
    '2' => 'somthin',
    array('0' =>'somethin here')
  )
)

OK. I have a MD array here with a nested array. (Not sure what to call it) How would I refer to the nested array with a foreach?

[fjm]

take a look at this: its a visual example of a 4D array. hope this helps.

and indeed you create it by putting an array in a array. and that one in another array and that one in another and ... (you get the poin :) )

Great example Ciary, thanks. Is this a 4D array because each box has 4 columns or because each box has 4 columns? How did you determine that it was 4?

Please tell me that I wouldn't ever encounter an array like this. :)

[Dormilich]

Scary thought because each cell or array can have an infinite number of arrays. It blows my mind to even imagine it.

you haven't seen where such array are used in reality…

OK. I have a MD array here with a nested array. (Not sure what to call it)

call it MD or nested array.

How would I refer to the nested array with a foreach?

which one? you have a total of 4 arrays…

$array
$array[0]
$array[1]
$array[1][0]

although you might run into problems here:

array('0' => "value", "value")

because array(0 => x) and array(x) is the same and PHP is not strongly typed (i.e. it can easily switch variable types and the difference between 0 and '0' is not much)

[fjm]

[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant name - assumed 'name' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 4
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant occupation - assumed 'occupation' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 5
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant age - assumed 'age' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 6
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant specialty - assumed 'specialty' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 7
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant name - assumed 'name' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 11
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant occupation - assumed 'occupation' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 12
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant age - assumed 'age' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 13
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant specialty - assumed 'specialty' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 14
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant name - assumed 'name' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 18
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant occupation - assumed 'occupation' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 19
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant age - assumed 'age' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 20
[Tue Apr 21 02:23:06 2009] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant specialty - assumed 'specialty' in C:\\Program Files\\Apache Software Foundation\\Apache2.2\\htdocs\\acme\\3.php on line 21

hehe.. Thanks Dormilich, my errors are now back!

[Ciary]

foreach($array as $val){
   if($val[3]){
      echo $val[3][0];    //this will print 'somethin here'
   }
}

the 'if' is very important otherwise you will get an error because you try to echo something that doesnt exist.

[Dormilich]

Great example Ciary, thanks. Is this a 4D array because each box has 4 columns or because each box has 4 columns? How did you determine that it was 4?

the 4x5 (5x4) tables are 2D, then you have 3 rows making it 3D and 4 columns making 4D.

[Ciary]

it has nothing to do with row/column count. it's purely the number of dimentions. or better: the dept of the nested array.

$array = array(array(array(array())))

this is a 4D array

[fjm]

you haven't seen where such array are used in reality…

You're right. In every day practice, I couldn't see anything like that; thank God. I think that the most I could see would be a 2D or maybe a 3D array but I wouldn't think that I would have one over that.

Maybe a better example would be a 2D array.

$result = array
(
  array
  (
    'mykey0' => 'myvalue0',
    'mykey1' => 'myvalue1',
    'mykey2' => 'myvalue2'
  ),
  array
  (
    '0' => 'somthin',
    '1' => 'somthin',
    '2' => 'somthin',
    '3' => 'somthin else'
  )
)

Say that I wanted to get the value "somthin else".... Could I do..

foreach($result as $key => $val)
{
  echo $key['3'][$val];
}

Would this work?

[fjm]

it has nothing to do with row/column count. it's purely the number of dimentions. or better: the dept of the nested array.

$array = array(array(array(array())))

this is a 4D array

OK, thanks for that Ciary.. So it simply the number of "array"(s) in the statement. Yes? You say dimensions and I am thinking code block. These fancy terms just screw me up sometimes. :)

Atli once helped me and gave me an array to do something that I needed. "WILD" stuff, man.. It was 6 or 7 arrays (dimensions). I flipped out just looking at it.

[Markus]

With nested foreach loops.

foreach ( $array as $inner )
{
	foreach ( $inner as $key => $val )
	{
		if ( is_array($val) )
		{
			foreach( $val as $key => $val2 )
			{
				echo "{$key} => {$val2}<br />";
			}
		}
		else
		{
			echo "{$key} => {$val}<br />";
		}
	}
}

Sometimes hardcoding the loops will be out-of-the-question, so you'll need to a look see at recursion.

- mark.

[Dormilich]

Would this work?

no, $key is either string or integer (read here).

use

$result[1]['3']

[fjm]

I found it! Here is the array that Atli gave me that just flipped me out.

$pages = array(
    array(
        "Title" => "First page",
        "Tables" => array(
            array(
                "Title" => "First table",
                "Rows" => array(
                    array(
                        "Cells" => array("Col1", "Col2", "Col3")
                    ),
                )
            ),
            array(
                "Title" => "Second table",
                "Rows" => array(
                    array(
                        "Cells" => array("Col1", "Col2", "Col3")
                    )
                )
            )
        )
    )
);

To me.. If I can master getting data back out of this monster, I will be very happy in my newly found knowledge of arrays.