How can the use of single quotes versus double quotes impact the interpretation of variables in PHP code?

When using single quotes in PHP to define a string, variables within the string are not parsed and will be treated as literal text. On the other hand, when using double quotes, variables within the string will be parsed and their values will be included in the output. To ensure that variables are interpreted correctly within a string, use double quotes when defining the string. Example PHP code snippet:

$name = "John";
// Using double quotes to correctly interpret the variable
echo "Hello, $name!";