PHP constants, PHP constants What are the _php tutorials

PHP constants, what are the PHP constants

The define () function is used to define constants. Once a constant is defined, it can no longer be changed or undefined.

Examples of defining constants:

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The constant name and any other PHP tags follow the same naming conventions. A valid constant name begins with a letter or underscore followed by any letter, number, or underscore.

Changshime is considered case-sensitive, and by convention constant identifiers are always uppercase, and the value cannot be changed during script execution.

To define the difference between a constant and a defined variable:

• No dollar sign ($) before constant
• Constants can only be defined with the Define () function, not through assignment statements
• Constants can be defined and accessed anywhere without regard to the rules of variable scope
• Constants cannot be redefined or undefined once defined
• The value of a constant can only be scalar

PHP contains a number of pre-defined constants, which can be viewed in PHP manuals.

Original address: http://www.manongjc.com/php/php_constant.html

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