I have a shortcode in a theme that displays only when a user is logged out. Usually, I would use the following shortcode to achieve this
[logged_out]Content[/logged_out]
How would I achieve this in PHP?
<?php echo do_shortcode("[logged_out]"); ?>
Can you just try the code like below,
<?php
$string = 'Hello world';
echo do_shortcode('[logged_out]'.$string.'[/logged_out]');
?>
you can assign any value to the variable $string ;
Or you can directly use like this,
<?php
echo do_shortcode('[logged_out]Hello world[/logged_out]');
?>
For more information please refer,
https://developer.wordpress.org/reference/functions/do_shortcode/