Why do both of these work? Why does one need single quotes around the array key and the other doesn't?
echo '<li><a href="' . $item['slug'] . '">' . $item['title'] . '</a></li>';
echo "<li><a href=\"$item[slug]\">$item[title]</a></li>";
On the other hand, this doesn't work:
echo '<li><a href="$item[slug]">$item[title]</a></li>';
(it displays as $item[title] )
Items in single quotes get output verbatim, unprocessed Items in double quotes get processed
If you use curly braces, your editor will make it clear that the thing is a variable
echo "<li><a href=\"{$item['slug']}\">{$item['title']}</a></li>";
Jason likes to use:
echo "<li><a href='{$item['slug']}'>{$item['title']}</a></li>";
If not including variables, definitely use single quotes all the time.