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This article will explain in detail what are the differences between const and define in php. The editor thinks it is very practical, so I share it with you for reference. I hope you can get something after reading this article.

The differences between const and define in php are: const is a language structure, define is a function; const can be used in a class, but define cannot; const cannot be used in a conditional branch, define can.

This article operating environment: windows10 system, php 7, thinkpad T480 computer.

We know that there are two ways to define constants in PHP, const and define. So many beginners may have a question when using const and define: what is the difference between them?

Let's look at the difference between the two:

Const is a language construct, while define is a function.

Const can be used in classes, but define cannot. Before PHP5.3, const could only be used in a class, while PHP5.3 could be used outside a class.

Const cannot be used in conditional branches, while define can.

Const can only use normal constant names, and define can use expressions.

Const only accepts static scalars before PHP5.6. Expressions can be used from PHP5.6, and expressions can be used by define.

The constants defined by const are case-sensitive, while define can specify whether it is case-sensitive by a third parameter (true is not sensitive; false is sensitive, default is false).

Const takes namespaces into account when defining constants, while define does not. To put it simply, const can define constants of the same name in different namespaces, while define cannot.

Constants can be accessed directly through the constant name or through the constant () function, and all defined constants can be obtained through get_defined_constants ().

This is the end of the article on "what are the differences between const and define in php". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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