Use php echo to output html, how to output variables correctly

Question

For example

<?php
$tf = "true";
echo '<dt class="qp-ui" data-qp-ui="{ \'SideNavZippy\': 变量输出位置 }"></dt>';
?>

How to correctly output variables in echo html? Thanks

Answer 1

echo '<dt class="qp-ui" data-qp-ui="{ \'SideNavZippy\': ' . $tf . ' }"></dt>';