Interpolation in PHP

Interpolation in PHP refers to the ability to embed variables directly into a string without the need for concatenation. This can be achieved using double quotes ("") or heredoc syntax. Here are some examples:

1. Using double quotes:

$name = "John";
$message = "Hello, $name!";
echo $message; // Output: Hello, John!

2. Using curly braces:

$age = 25;
$message = "I am {$age} years old.";
echo $message; // Output: I am 25 years old.

3. Using heredoc syntax:

$name = "Mary";
$message = <<