PHP show articles in row's and div's repeating - php

Question

I'm trying to create some div's that are supposed to be some articles in a webshop using bootstrap 4 alpha and PHP.
I think I need modulo (%) for this but I can't achieve what I want, I have read this and tried playing around with it but I can't get it to work, because I don't really understand what it does.
What I need is 1 row, 4 columns, and this repeating. I hope you understand where I'm going.
Here is the HTML example, there could be more rows and div's as you can see in the PHP below it:
<div class="row">
<div class="sm-col-3">
<div class="card-deck-wrapper">
<div class="card-deck">
<div class="card card-outline-secondary">
<img class="card-img-top m-x-auto d-block placeholder" src="empty.png" alt="Product">
<div class="card-block">
<h4 class="card-title">Product</h4>
<p class="card-text">
<span>Omschrijving van het product. </span><br>
<span>€ 1,00</span><br>
<span>Voorraad: 1</span>
</p>
Koop
</div>
</div>
<div class="card card-outline-secondary">
<img class="card-img-top m-x-auto d-block placeholder" src="empty.png" alt="Product">
<div class="card-block">
<h4 class="card-title">Product</h4>
<p class="card-text">
<span>Ik zal hier ook maar wat in knallen zodat niet alle kaarten even groot zijn.</span><br>
<span>€ 1,00</span><br>
<span>Voorraad: 1</span>
</p>
Koop
</div>
</div>
<div class="card card-outline-secondary">
<img class="card-img-top m-x-auto d-block placeholder" src="empty.png" alt="Product">
<div class="card-block">
<h4 class="card-title">Product</h4>
<p class="card-text">
<span>Deze kaart zal ook net even iets groter zijn om het uit te testen want ik snap er geen reet van.</span><br>
<span>€ 1,00</span><br>
<span>Voorraad: 1</span>
</p>
Koop
</div>
</div>
<div class="card card-outline-secondary">
<img class="card-img-top m-x-auto d-block placeholder" src="empty.png" alt="Product">
<div class="card-block">
<h4 class="card-title">Product</h4>
<p class="card-text">
<span>Omschrijving van het product.</span><br>
<span>€ 1,00</span><br>
<span>Voorraad: 1</span>
</p>
Koop
</div>
</div>
</div>
</div>
</div>
</div>
<div class="row">
<div class="sm-col-3">
<div class="card-deck-wrapper">
<div class="card-deck">
<div class="card card-outline-secondary">
<img class="card-img-top m-x-auto d-block placeholder" src="empty.png" alt="Product">
<div class="card-block">
<h4 class="card-title">Product</h4>
<p class="card-text">
<span>Omschrijving van het product.</span><br>
<span>€ 1,00</span><br>
<span>Voorraad: 1</span>
</p>
Koop
</div>
</div>
<div class="card card-outline-secondary">
<img class="card-img-top m-x-auto d-block placeholder" src="empty.png" alt="Product">
<div class="card-block">
<h4 class="card-title">Product</h4>
<p class="card-text">
<span>Omschrijving van het product.</span><br>
<span>€ 1,00</span><br>
<span>Voorraad: 1</span>
</p>
Koop
</div>
</div>
</div>
</div>
</div>
PHP what I have now:
$categorie = mysqli_real_escape_string($mysqli, $_GET['categorie']);
$sql = "SELECT * FROM producten WHERE categorie = '$categorie' AND voorraad > 0";
$result = mysqli_query($mysqli, $sql) or die(mysqli_error($mysqli));
if (mysqli_num_rows($result) == 0) {
echo "<div class=\"card card-inverse card-warning text-xs-center\">\n";
echo " <div class=\"card-block\">\n";
echo " <blockquote class=\"card-blockquote\">\n";
echo " <span>Deze categorie bestaat niet!</span>\n";
echo " </blockquote>\n";
echo " </div>\n";
echo "</div>\n";
}
else {
echo "<h3>Categorie: " . ucfirst($_GET['categorie']) . "</h3>\n";
$i = 0;
while ($row = mysqli_fetch_array($result)) {
if ($i % 3 == 0) {
echo "<div class=\"row\">\n";
echo " <div class=\"sm-col-3\">\n";
echo " <div class=\"card-deck-wrapper\">\n";
echo " <div class=\"card-deck\">\n";
}
echo " <div class=\"card card-outline-secondary\">\n";
if ($row['plaatje'] == "") {
echo " <img class=\"card-img-top m-x-auto d-block placeholder\" src=\"empty.png\" alt=\"". $row['naam'] . "\">\n";
}
else {
echo " <img class=\"card-img-top m-x-auto d-block placeholder\" src=\"" . $row['plaatje'] . "\" alt=\"". $row['naam'] . "\">\n";
}
echo " <div class=\"card-block\">\n";
echo " <h4 class=\"card-title\">" . $row['naam'] . "</h4>\n";
echo " <p class=\"card-text\">\n";
echo " <span>" . nl2br($row['omschrijving']) . "</span><br>\n";
echo " <span>€ " . str_replace(".", ",", number_format($row['prijs'], 2)) . "</span><br>\n";
echo " <span>Voorraad: " . $row['voorraad'] . "</span><br>\n";
echo " </p>";
echo " Koop\n";
echo " </div>\n";
echo " </div>\n";
if ($i % 3 == 2) {
echo " </div>\n";
echo " </div>\n";
echo " </div>\n";
echo "</div>\n";
}
if ($i % 3 != 0) {
echo " </div>\n";
echo " </div>\n";
echo " </div>\n";
echo "</div>\n";
}
$i++;
}
It's probably a easy solution but I can't see it!
Thanks for your time.

Answer 1

From the link in your question, this works for me:
$i = 0;
while ($row = mysqli_fetch_array($result)) {
if ($i % 3 == 0){
echo '<div class="row">';
}
echo '<div class="col-lg-4 col-md-4 col-sm-4">';
//Your column data here
echo '</div>';
if ($i % 3 == 2){
//Close the .row div
echo '</div>';
}
$i++;
}
if ($i % 3 != 0){
//Close the .row div in case there aren't enough items left to fill up to 3
echo '</div>';
}
http://www.devchunks.com/web-development/using-the-php-modulus-operator/