title: PHP Help with "if" statement to dynamically include files
body: <p>I have these files:</p>
  
  <p>"id_1_1.php", "id_1_2.php", "id_1_3.php" etc
  "id_2_1.php", "id_2_2.php", "id_2_3.php" etc</p>
  
  <p>the number of files is not known because will always grow..</p>
  
  <p>all the files are in same directory..</p>
  
  <p>I want to make a if statement:</p>
  
  <ol>
  <li>to include the files only if their name ends with "_1"</li>
  <li>another function to load all the files that start with "id_1"</li>
  </ol>
  
  <p>How can I do this? Thank you!</p>
  
  <p>edit1: no the numbers will not be skipped, once I have another item for id_1_ collection of products I will add new ones as id_1_1, id_1_2 etc.. so no skipping..</p>