What is the difference between single and double quotes in PHP?

In PHP, single quotes and double quotes are used to define strings. The main difference between them is that single quotes are literal, meaning they interpret the string exactly as it is written, while double quotes allow for the interpretation of variables and special characters within the string. To fix issues related to single or double quotes in PHP, you should be aware of when to use each type based on the requirements of your string. If you need to include variables or special characters within the string, you should use double quotes. If you want a literal interpretation of the string without any special characters or variables being evaluated, you should use single quotes.

// Using single quotes for a literal string
$string1 = 'Hello, World!';

// Using double quotes to allow for variable interpolation
$name = 'Alice';
$string2 = "Hello, $name!";