Adding post_class into functions.php query

by

  • post_class() will echo the class in the format class="postclassA
    postclassB"
  • get_post_class() will return an array of all registred
    classes

To use get_post_class() inside sprintf(), you have to return the array as a string. For this purpose you can use the join() function.

Example

$classes = join(' ', get_post_class())
$sidebar = sprintf('<div id="post-%s" class="%s">%s</div>', get_the_ID(), $classes, get_the_content());