Detailed explanation of global variables in PHP_PHP tutorial
This article will introduce in detail the method of global variable global in PHP. Friends who need to know how to use the global function can refer to this article.
The scope of a variable is the context in which it is defined (that is, its effective scope). Most PHP variables have only a single scope. This single scope span also includes files introduced by include and require. For example:
The code is as follows | Copy code | ||||
include 'b.inc'; ?>
|
代码如下 | 复制代码 |
$a = 1; /* global scope */ function Test() Test(); |
The code is as follows | Copy code |
$a = 1; /* global scope */ function Test() Test(); |
代码如下 | 复制代码 |
$a = 0 ; function Test() { $a =1; } Test(); echo $a; ?> |
Today I encountered the problem that php global variables do not work.
代码如下 | 复制代码 |
$a = 0 ; function Test() { global $a;//申明函数体Test内使用的$a变量为global全局变量 $a =1; } Test(); echo $a; ?> |
After declaring the $a variable used in the function body Test as a global global variable, $a has a global effect, so the output is 1.
The above examples are just basic knowledge of global variables. Let’s look at more complicated ones:
//A.php file
The code is as follows
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Copy code
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function Test_Global() {Include 'B.php'; Test();}
Test_Global(); echo $a;
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