php string literal

<?php
$str = <<<EOD
Example of string
spanning multiple lines
using heredoc syntax.
EOD;

/* More complex example, with variables. */
class foo
{
    var $foo;
    var $bar;

    function __construct()
    {
        $this->foo = 'Foo';
        $this->bar = array('Bar1', 'Bar2', 'Bar3');
    }
}

$foo = new foo();
$name = 'MyName';

echo <<<EOT
My name is "$name". I am printing some $foo->foo.
Now, I am printing some {$foo->bar[1]}.
This should print a capital 'A': \x41
EOT;
?>

sprintf('a %s string with placeholder %s %s %s', $var, ...$array); 
// n additional variables can be passed to sprintf function, or can be passed in an array using the spread opperator in PHP 8.2+

Double Quotes:
"variable {$var} is inline, inside double quotes"

Single Quotes:
'Variable is appended using dots ' . $var . ' to the string.'; 

Newdoc Syntax:
$str = <<<'STR'
Variable is $var
STR;

Heredoc Syntax:
$str = <<<STR
Variable is $var
STR;