PHP: How do you determine every Nth iteration of a loop? - php

Question

I wanted to echo an image every after 3 post via XML here is my code :
<?php
// URL of the XML feed.
$feed = 'test.xml';
// How many items do we want to display?
//$display = 3;
// Check our XML file exists
if(!file_exists($feed)) {
die('The XML file could not be found!');
}
// First, open the XML file.
$xml = simplexml_load_file($feed);
// Set the counter for counting how many items we've displayed.
$counter = 0;
// Start the loop to display each item.
foreach($xml->post as $post) {
echo '
<div style="float:left; width: 180px; margin-top:20px; margin-bottom:10px;">
image file</a> <div class="design-sample-txt">'. $post->author.'</div></div>
';
// Increase the counter by one.
$counter++;
// Check to display all the items we want to.
if($counter >= 3) {
echo 'image file';
}
//if($counter == $display) {
// Yes. End the loop.
// break;
//}
// No. Continue.
}
?>
here is a sample first 3 are correct but now it doesn't loop idgc.ca/web-design-samples-testing.php

Answer 1

The easiest way is to use the modulus division operator.
if ($counter % 3 == 0) {
echo 'image file';
}
How this works:
Modulus division returns the remainder. The remainder is always equal to 0 when you are at an even multiple.
There is one catch: 0 % 3 is equal to 0. This could result in unexpected results if your counter starts at 0.

Answer 2

Going off of #Powerlord's answer,
"There is one catch: 0 % 3 is equal to 0. This could result in
unexpected results if your counter starts at 0."
You can still start your counter at 0 (arrays, querys), but offset it
if (($counter + 1) % 3 == 0) {
echo 'image file';
}

Answer 3

Use the modulo arithmetic operation found here in the PHP manual.
e.g.
$x = 3;
for($i=0; $i<10; $i++)
{
if($i % $x == 0)
{
// display image
}
}
For a more detailed understanding of modulus calculations, click here.

Answer 4

every 3 posts?
if($counter % 3 == 0){
echo IMAGE;
}

Answer 5

You can also do it without modulus. Just reset your counter when it matches.
if($counter == 2) { // matches every 3 iterations
echo 'image-file';
$counter = 0;
}

Answer 6

How about: if(($counter % $display) == 0)

Answer 7

I am using this a status update to show a "+" character every 1000 iterations, and it seems to be working good.
if ($ucounter % 1000 == 0) { echo '+'; }

Answer 8

It will not work for first position so better solution is :
if ($counter != 0 && $counter % 3 == 0) {
echo 'image file';
}
Check it by yourself. I have tested it for adding class for every 4th element.