I have been working on a PHP project for some time now and I have come across constants in code. I have been using variables quite extensively, but I am unsure about how to use constants and if they can be used in the same way as variables. Can anyone help me understand if constants can be used as variables in PHP code? Thanks in advance!

Sure! I've been using PHP for quite some time now, and I can confirm that constants are indeed an essential part of the language. While they have some similarities with variables, there are some key differences in how you use them.
In PHP, constants, as the name suggests, hold values that remain constant throughout the execution of your code. Unlike variables, constants cannot be changed once they are defined. This immutability is particularly useful when you have values that should never be modified.
To define a constant in PHP, you can use the `define()` function, followed by the constant name and its value. For example:
Here, I've defined a constant called "DATABASE_NAME" with a value of "my_database". You can then use this constant anywhere in your code, just like a variable, by simply referencing its name (`DATABASE_NAME` in this case).
One important thing to note is that constants are always global in scope. This means that once defined, you can access them from anywhere within your code, without any additional steps.
Using constants can greatly enhance the readability of your code, as they provide meaningful names for values that should not be altered. They also help prevent accidental modification, ensuring the integrity of your program.
I hope this explanation helps you understand how to use constants in PHP. Feel free to ask if you have any further questions!