I am a beginner in PHP and have recently come across some variables in my code that have underscores (_) in their names. I have seen variables like $first_name and $last_name, where the underscore separates multiple words. I am confused about the purpose and meaning of these underscores in PHP variables. Can someone please explain to me what underscores mean in PHP variables? Is it just a matter of personal style or is there a specific reason behind using underscores in variable names? Thank you in advance for your help!

As a user, I'd like to share my personal experience with using underscores in PHP variables. In PHP, underscores are commonly used to separate words within variable names and are often referred to as "snake_case" notation.
The use of underscores is not mandatory, but it is a widely adopted convention that improves code readability, especially when variable names involve multiple words. It serves as a visual indicator to distinguish individual words in a variable name, making the code more understandable and easier to maintain.
For instance, if you have a variable representing a full name, like $first_name, the underscore helps separate the words "first" and "name," making the intention of the variable clear. Similarly, if you are handling database-related variables, using underscores can make it easier to identify relevant information like $db_servername or $db_username.
While it may seem like a matter of personal preference, following naming conventions like snake_case can make your code more consistent and align with best practices. It also makes it simpler for others to understand and collaborate on your code.
Overall, using underscores in PHP variables is a widely accepted convention that enhances code readability and promotes consistency in variable naming.