Echo a field of Advanced Custom Fields, if it is present. You may prepend and append it with custom strings (HTML ;) )

the_field_if.php

<?php

/**
 * Echo an ACF Field if it is present
 * @param bool|int   $field Name of the field
 * @param string $before prepend the field with this string. HTML for example
 * @param string $after append the field with this string. HTML for example
 * @param bool|int   $post_id
 *
 * @return bool|void
 * @author Markus Schober
 */
function the_field_if($field = false, $before = '', $after = '', $post_id = false)
{
    if ( get_field($field, $post_id) ) {
        echo $before . get_field($field, $post_id) . $after;
    }
    else {
        return false;
    }
}