Question

I store post IDs in an array. I would like to loop through the array and display the IDs within a <div> containing <p> and <ul> tags, but only when at least one ID is in the array. If the array is empty no html can be returned. This implies that I should use some kind of if statement before the loop. Needless to say, my php skills are pretty basic and after two days of trying hard I am getting nowhere. Grateful for help!

My code (using WordPress)

$postids = array();

...

$postids [] = $post->ID; //stores the post IDs in the array

Here is an update. I apologize for posting all this code as its quite messy with many things going on. It’s the second loop of three (or more). The IDs displayed in a near identical first loop have been passed on. Only those IDs which have not been retrieved by the previous loop are displayed in order not to show any duplicate posts.

I have tried to remove all HTML markup and query the $postids with a new WP_Query after but that retrieves all posts I have ever created. I am pretty sure that’s the right way to continue although I am obviously doing something wrong.

<?php
$tags = wp_get_post_tags($post->ID);
if ($tags) {
  $first_tag = $tags[1]->term_id;
  $args=array(
    'tag__in' => array($first_tag),
    'post__not_in' => array($post->ID),
    'showposts'=>5, //Display this number of related posts
    'ignore_sticky_posts'=>1
   );
  $postids = array();
  $my_query = new WP_Query($args);
  if( $my_query->have_posts() ) {
      echo '<ul id="relatedposts">'; 
      while ($my_query->have_posts()) : $my_query->the_post(); if (!in_array($post->ID, $ids)) {; $postids [] = $post->ID; ?>
      <li><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></li>
      <?php }
    $ids[]= $post->ID; 
    endwhile;
  }
}
?>
      </ul>
<?php if ($postids){ //$postids has at least one value set
    echo '<div>Related posts</div>'; //Outputting the header text. This works! If there are no IDs in the array nothing is shown.
     }; 
?>

Answer 1

This should work:

 <?php

 // assuming you have an array of ids called $postids

 if(count($postids)){
    echo "<div><ul>";
    foreach($postids as $id){
       echo "<li>$id</li>";
    }
    echo "</ul></div>";
 }


 ?>

To break it down:

if(count($ids)){

count() returns the number of elements in the array $ids. Any number other than zero will evaluate to true and enter the if statement, zero will evaluate to false and the whole thing will be skipped.

 foreach($ids as $id){

This loops through each element in the array $ids and assigns it to the variable $id. Hopefully the echo statements are self explanatory.