How to set constants in php
How to set constants in php: 1. Use the define() function, the syntax "define('constant name', 'constant value')"; 2. Use the const keyword, the syntax "const constant name = constant value;".
The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer
The so-called constant is a quantity that cannot be changed, in PHP Once a constant is defined, it cannot be modified or undefined.
PHP constants are usually used to store data that does not change and is not expected to change. The data can only be data of four scalar data types: integer, floating point, string, and Boolean. However, Starting from PHP7, constants support array types.
How to set constants
1. Use the define() function
Legal constants A name can only begin with a letter and an underscore, and can be followed by any length of letters, numbers, or underscores. In PHP, you can define a constant through the define() function. The syntax of the define() function is as follows:
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define() The description of the function parameters is as shown in the following table:
Parameters | Description |
---|---|
$name | Required parameter, constant name (needs to be wrapped in double quotes or single quotes) |
$value | Required parameter, constant value |
$case_insensitive | Optional parameter, Specify whether to be case-sensitive. The default is case-sensitive. If set to true, it means case-insensitive |
2. Use the const keyword
In addition to using the define() function, you can also use the const keyword to define constants. The syntax of the const keyword is as follows:
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The following uses examples to demonstrate the use of constants:
1 2 3 4 5 6 7 |
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Running results:
Recommended learning: "PHP Video Tutorial"
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