Multidimensional Arrays

Neko_D

So I am trying to figure out Multidimensional Arrays in PHP. So I want to make a simple array that houses the sum of it position in the array,:queasy: Something like $array[5][6] contains the value 11. So I doctored up the following function to do that.

$nums;
function buildArrayOne()
{
for($tick = 0; $tick < 20; $tick++)
{
for($tock = 0; $tock < 30; $tock++)
{
$num[$tick][$tock] = $tick + $tock;
}//end tock for
}//end tick for
}//end buildArrayOne

And then I want to output the results to a table using this function:
function displayArrayNestedFors($arr)
{
for($row = 0; $row < 10; $row++)
{
print "<tr>";
for($col = 0; $col < 20; $col++)
{
$disp = $nums[$row][$col];
print "<td>$disp</td>";
}//end col for
print "</tr>";
}//end row for
}//end displayArrayNestedFors

But whenever I run the script it displays nothing. Can someone tell me why, and how to fix it?

I am currently using a book called "Teach Yourself PHP in 24 hours" I really like the book it just lacks some description and explanation that I would like to have. All of the multidimensional arrays in that book are associative arrays. While a nice feature they are a pain in the ass to build up.

Anyway thanks for any help.

NogDog

Do you ever actually call your displayArrayNestedFors() function anywhere in the script?

Neko_D

NogDog wrote:
Do you ever actually call your displayArrayNestedFors() function anywhere in the script?

:eek: OMG.....:glare: yes.

So I take it that I am initializing the array correctly? Try running the script on your own.

NogDog

You have a discrepancy in variable names. You start out calling the array $nums, but refer to it as $num on the line that populates the values.

Anyway, here's a somewhat streamlined version utilizing the foreach loop technique for the output, which you might find useful:

<table>
<?php
$nums = array();
for($tick = 0; $tick < 20; $tick++)
{
   for($tock = 0; $tock < 30; $tock++)
   {
      $nums[$tick][$tock] = $tick + $tock;
   }//end tock for
}//end tick for

foreach($nums as $row)
{
   echo "<tr>";
   foreach($row as $col)
   {
      echo "<td>$col</td>";
   }
   echo "</tr>\n";
}
?>
</table>

Neko_D

NogDog wrote:
You have a discrepancy in variable names. You start out calling the array $nums, but refer to it as $num on the line that populates the values.

Anyway, here's a somewhat streamlined version utilizing the foreach loop technique for the output, which you might find useful:
<table>
<?php
$nums = array();
for($tick = 0; $tick < 20; $tick++)
{
   for($tock = 0; $tock < 30; $tock++)
   {
      $nums[$tick][$tock] = $tick + $tock;
   }//end tock for
}//end tick for

foreach($nums as $row)
{
   echo "<tr>";
   foreach($row as $col)
   {
      echo "<td>$col</td>";
   }
   echo "</tr>\n";
}
?>
</table>

:quiet: I see I see, I do not have a PHP IDE :p my bad thanks for the help. Also thanks for showing me how to iterate using foreach loops, in this case, I was unsure of how exactly to do it.

On a side note, I have a question about associative arrays. What exactly does => mean?

NogDog

=> is an operator which can be used in certain contexts to indicate an array key on the left and its associated value on the right. For instance, you could define the same array in these two ways:

$arr[1] = "value 1";
$arr['two'] = "value 2";
$arr['three'] = "value 3";

// ...or...

$arr = array(1 => "value 1", 'two' => "value 2", 'three' => "value 3");

Note that it can be used for any type of array, not just associative ones.

Neko_D

I see I see, thanks so much NogDog.