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The define() function defines a constant.
define()函数的作用是:定义一个常量。
Constants are much like variables, except for the following differences:
常量[constant]与变量[variable]有很多相似的地方,因此,很容易混淆;下面,我们列举一下常量[constant]与变量[variable]之间的不同点:
define(name,value,case_insensitive) |
Parameter 参数 | Description 描述 |
---|---|
name | Required. Specifies the name of the constant 必要参数。指定常量的名称 |
value | Required. Specifies the value of the constant 必要参数。指定常量的值 |
case_insensitive | Optional. Specifies whether the constant name should be case-insensitive. If set to TRUE, the constant will be case-insensitive. Default is FALSE (case-sensitive) 可选参数。指定常量的名称是否是不区分大小写的[case-insensitive]。如果设置为True,则不区分字母大小写;如果设置为False,则区分字母大小写。默认值是:False |
Define a case-sensitive constant:
指定一个常量(区分大小写):
<?php define("GREETING","Hello you! How are you today?"); echo constant("GREETING"); ?> |
The output of the code above will be:
上述代码将输出下面的结果:
Hello you! How are you today? |
Define a case-insensitive constant:
指定一个常量(不区分大小写):
<?php define("GREETING","Hello you! How are you today?",TRUE); echo constant("greeting"); ?> |
The output of the code above will be:
上述代码将输出下面的结果:
Hello you! How are you today? |