PHP constants are comparable to the simpler types of data variables (strings, floats, booleans, and integers) as they can only store scalar data. As the name itself suggests, the value of every PHP constant is constant: it cannot be modified. Show While variables didn't require any special creation process, constants don't work if a developer hasn't defined them. You have to make PHP define constants using a
PHP Constant: Main Tips
define() Function ExplainedTo create a PHP constant, you have to use the function called
A name of a PHP constant has to abide by the same rules as the name of a variable. It must begin with a letter or underscore (_) but can contain as many letters or numbers as you like. The value it holds has to be scalar data (it cannot, for example, be used to store PHP arrays). Pros
Main Features
Pros
Main Features
Pros
Main Features
Standard Syntax RevealedThe following example reveals how it should look in your script when you PHP define constant before using it for the first time: Example
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Look at the example in which we will PHP define constant. You will notice the last parameter is skipped, therefore the result is a case-sensitive PHP constant name: Example
Now let's try to make a case-insensitive name. It's simple: all we need to do is set the last parameter to true, thus declaring the name is indeed case-insensitive: Example
PHP Constant: Summary
How constants are used in PHP?A constant is an identifier (name) for a simple value. The value cannot be changed during the script. A valid constant name starts with a letter or underscore (no $ sign before the constant name). Note: Unlike variables, constants are automatically global across the entire script.
How is a constant defined in PHP by using the keyword?Constants can be defined using the const keyword, or by using the define()-function. While define() allows a constant to be defined to an arbitrary expression, the const keyword has restrictions as outlined in the next paragraph. Once a constant is defined, it can never be changed or undefined.
How do you use a constant?You use the Const statement to declare a constant and set its value. By declaring a constant, you assign a meaningful name to a value. Once a constant is declared, it cannot be modified or assigned a new value. You declare a constant within a procedure or in the declarations section of a module, class, or structure.
How do you call a class constant in PHP?PHP - Class Constants
Constants cannot be changed once it is declared. Class constants can be useful if you need to define some constant data within a class. A class constant is declared inside a class with the const keyword. Class constants are case-sensitive.
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