PHP: Troubles on indexing a nested for-loop

Question

I am trying to print a 3-dimensional array into a table. But the indexes are kinda fked up. When I use the following (psuedo)code:

...
<<print headers and stuff>>

for ( $i = 0; $i < count( $array ); i++) {
    $itemArray = $array[i];

    for ( $j = 0; $j < count( $itemArray; j++) {
        $innerItem = $itemArray[j];
        echo <<tr start + both indexes in td>>

        foreach ($innerItem as $spec) {
            echo <<td with item>>
        }

        echo <<tr stop>>
    }
}

In this example I am using i as index for the outer array and j as an index for the inner array (pretty obvious). The result I am getting from this is as follows:

| index i | index j | title1 | title2 |
|    0    |    0    |        |        |
|    1    |    0    |        |        |
|    2    |    0    |        |        |
|   ...   |   ...   |        |        |

Whilst I would expect:

| index i | index j | title1 | title2 |
|    0    |    0    |        |        |
|    0    |    1    |        |        |
|    1    |    0    |        |        |
|    1    |    1    |        |        |
|    1    |    2    |        |        |
|    2    |    0    |        |        |
|   ...   |   ...   |        |        |

The (original) full code is:

echo "<h1>Combat analysis</h1>";
echo '<table cellspacing="0" cellpadding="4" border="1"><tbody>';
echo "<tr><td>#Mon</td><td>#Att</td><td>DungLVL</td><td>CharLVL</td><td>Health</td><td>Weapon</td><td>No. potions</td></tr>";
for ($battleIndex  = 0; $battleIndex < count($this->combatLog); $battleIndex++) {
    $battle = $this->combatLog[$battleIndex];
    for ($attackIndex = 0; $attackIndex < sizeof($battle); $attackIndex++) {
        $attack = $battle[$attackIndex];
        echo "<tr><td>" . $battleIndex . "</td><td>" . $attackIndex . "</td>";
        foreach ($attack as $stat) {
            echo "<td>" . $stat . "</td>";
        }
        echo "</tr>";
    }
}
echo "</tbody></table>";

What is going wrong?

This just means that all your battles have size 1. Most likely the error is in the way you populate them, not in this code. — Ishamael
– Ishamael, Commented Feb 3, 2015 at 1:13

Alexandru Trandafir Catalin · Accepted Answer · 2015-02-03 01:34:49Z

Tested your code and runs as expected. You should do a echo '<pre>'.print_r($this->combatLog).'</pre>'; and debug the array contents.

Also I would recommend you the following:

1) You can use foreach instead of for, example: foreach ($this->combatLog as $battleIndex => $battle)

2) If you're not sure that a array contains values you should first do a: if (is_array($this->combatLog) && count($this->combatLog) > 0)

3) For simplicity and code maintenance I would first loop the multi-dimensional array and turn it into a one dimension called $attacks containing a array per each attack indexed by keys that you can recognize, ej:

$attacks=array();
$attacks[]=array(
'Mon'=>$battleIndex,
'Att'=>$attackIndex,
'DungLVL'=>isset($stat[0])?$stat[0]:null,
'CharLVL'=>isset($stat[1])?$stat[1]:null,
'Health'=>isset($stat[2])?$stat[2]:null,
'Weapon'=>isset($stat[3])?$stat[3]:null,
'Potions'=>isset($stat[4])?$stat[4]:null,
);

Then you could define some columns for example:

$columns=array(
    'Mon',
    'Att',
    'DungLVL',
    'CharLVL',
    'Health',
    'Weapon',
    'Potions',
);

Then print the table header like this:

echo '<tr>';
foreach ($columns as $column) {
  echo '<td>'.$column.'</td>';
}
echo '</tr>';

And print rows like this:

foreach ($attacks as $attack) {
  echo '<tr>';
  foreach ($columns as $column) {
    echo '<td>'.$attack[$column].'</td>';
  }
  echo '</tr>';
}

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