loop_sample.php

<?php

/**
 * This is a sample function to illustrate your loop.
 */
function your_function() {
   $displayed_full_content = false;
   $posts = new WP_Query( /* your query args here*/ );
   
   while ( $posts->have_posts() ) {
       $posts->the_post();
       
       // For the first post, display the full content.
       if ( ! $displayed_full_content ) {
           the_content();
           $displayed_full_content = true;
       } else {
           the_excerpt();
       }
   }
   
   // When using a custom loop, it's always good practice to restore the regular post data.
   wp_reset_postdata();
}

Thanks, this is really useful!