Using foreach() with a multidimensional array

Question

I have a mySQL table which can be simplified down to something like this:

animal      breed
Cat         Persian
Cat         Siamese
Dog         Alsatian
Dog         Poodle

I want to display the information in this form:

<table>
<tr>
<td class="heading">Cat</td>
</tr>
<tr>
<td class="body">Persian</td>
<td class="body">Siamese</td>
</tr>
<tr>
<td class="heading">Dog</td>
</tr>
<tr>
<td class="body">Alsatian</td>
<td class="body">Poodle</td>
</tr>
</table>

So far, I have a query like this:

$query = "SELECT * FROM aa_animal";
$result = mysql_query($query, $MySQL_extranet) or die(mysql_error());
while($row = mysql_fetch_assoc($result)){
    $resultarray[] = $row;
}

Then I think I am going to need a pair of nested foreach() loops, but it is the handling of the multi-dimensional array that gets me hopelessly lost.

foreach("unique_animal") {
  <tr>
    <td class-"heading">$animal</td>
  </tr>
  if ($animal=="unique_animal") {
    foreach("row") {
    <tr>
      <td class-"body">$breed</td>
    </tr>
  }
}

How do I manipulate $resultarray to get the right values for $animal, $breed, etc?

PROGRESS SO FAR

Justin's reply provided the solution to the problem as described above. However the real-life page has a lot more columns in the database table. Here is the code for a halfway file between the simple example I gave originally and the page I am trying to create.

<?php

$countryid='spain';

// MySQL query to select hotels and display all the hotel info
$query = "SELECT hid, hotel, pricefrom, place, region, country, picture, property, prop2, rooms, summary, lat, lng, zoomloc, breakfast, searchparam, specialoffer, biz_model, ta_rating, bc_rating FROM ex_hotel WHERE country LIKE '%$countryid%' AND showhide = 'show' ORDER BY orderr DESC";
$result = mysql_query($query, $MySQL_extranet) or die(mysql_error());
while($row = mysql_fetch_assoc($result)) {
   if (isset($resultarray[$row['region']])) {
      $resultarray[$row['region']][] = $row['hotel'];
   }else{
      $resultarray[$row['region']] = array($row['hotel']);
   }
}
ksort($resultarray);
?>

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
</head>

<body>
<table width="500" border="1" cellspacing=" 4" cellpadding="4">
<?php foreach($resultarray as $region => $hotel)
{
   echo '<tr><td colspan="2" style="background-color:#ddd">'.$region.'</td></tr>';

   foreach($hotel as $value) {
      echo '<tr><td width="250px">'.$value.'</td>';
   }
   foreach($hid as $value2) {
      echo '<td>'.$value2.'</td></tr>';
   }
}?>
</table>
</body>
</html>

All those values in the mySQL query need to be used in the table, but how do I get them?

First things first, I believe you should have a look at foreach syntax: nl3.php.net/manual/en/control-structures.foreach.php. — lucke84
– lucke84, Commented Feb 8, 2014 at 17:33
Also you should consider ordering/grouping the results of your query, if you want to display all cats first, then all dogs, etc. — lucke84
– lucke84, Commented Feb 8, 2014 at 17:34

Justin Iurman · Accepted Answer · 2014-02-08 19:31:30Z

2

You should group data when fetching

while($row = mysql_fetch_assoc($result))
{
   if (isset($resultarray[$row['animal']]))
      $resultarray[$row['animal']][] = $row['breed'];
   else
      $resultarray[$row['animal']] = array($row['breed']);
}

And then, display it

foreach($resultarray as $animal => $breed)
{
   echo '<tr><td class="heading">'.$animal.'</td></tr>';

   foreach($breed as $value)
      echo '<tr><td class="body">'.$value.'</td></tr>';
}

EDIT: If you need more columns, what you have to do is storing full row instead of one item:

while($row = mysql_fetch_assoc($result))
{
   if (isset($resultarray[$row['region']]))
      $resultarray[$row['region']][] = $row;
   else
      $resultarray[$row['region']] = array($row);
}

And then, you can also fetch those rows

foreach($resultarray as $region => $rows)
{
   echo '<tr><td class="heading">'.$region.'</td></tr>';

   // this way (display everything)
   foreach($rows as $row)
      foreach($row as $key => $value)
         echo '<tr><td class="body">'.$key.': '.$value.'</td></tr>';

   // or this way (if you want to display only specific item)
   foreach($rows as $row)
      echo '<tr><td class="body">Hotel: '.$row["hotel"].' / price: '.$row["pricefrom"].'</td></tr>';
}

edited Feb 8, 2014 at 19:31

answered Feb 8, 2014 at 17:36

Justin Iurman

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5 Comments

TrapezeArtist Over a year ago

Amazing! I just copied and pasted Justin's code without even pausing to understand it, and it worked. Thanks, Justin. Now all I have to do is scale up the logic to work on my real-life page.

TrapezeArtist Over a year ago

Inevitably, I have hit a problem in trying to scale-up. In reality there are about 10 or 15 columns in the table, not just the two. How do I handle them? Is it possible to do something like foreach($resultarray as $animal => $breed, $legs, $fur) to create variables from the other columns?

Justin Iurman Over a year ago

Not like you said. It is hard to give you an answer on the fly without knowing utility of other columns and what you want to do with them

TrapezeArtist Over a year ago

I'll update my original question with the test file as it currently stands.

TrapezeArtist Over a year ago

It says here I should avoid comments like "thanks", but what else can I say. Huge thanks to Justin. Hopefully this will teach me enough about arrays to be able to apply them to other things in the future.

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