Is it possible to write variables with keys in a string?

Question

PHP

Hello. I need to collect the HTML code as a string and send it to the client. I need to fill this code with variables. The problem is that the variables are from an array and they all have keys. That is, I need to specify variables with keys in the line.
This does not work:

foreach ($orders['entries'] as $o) {
$htmlorder[] = "<td class='id'>$o['_id']</td>";
}

The only option is to isolate the variables with quotes with dots? Or is there some other syntax?

Answer 1

Wrap with curly braces

foreach ($orders['entries'] as $o) {
$htmlorder[] = "<td class='id'>{$o['_id']}</td>";
}

Answer 2

There is another option without curly braces. But I would strongly advise against using it.

foreach ($orders['entries'] as $o) {
$htmlorder[] = "<td class='id'>$o[_id]</td>";
}