What is the significance of using single quotes vs double quotes in PHP strings?

In PHP, using single quotes ('') and double quotes ("") to define strings can have different implications. Single quotes are more literal and do not interpret variables or special characters within the string, while double quotes do. Therefore, if you want to use variables or special characters within a string, you should use double quotes. However, single quotes can be more efficient for simple string declarations where variable interpolation is not needed.

$name = 'Alice';

// Using double quotes for variable interpolation
echo "Hello, $name!";

// Using single quotes for a literal string
echo 'Hello, $name!';