About the different distinctions between global variables global and $GLOBALS in PHP - WORSHIP Yasa

1.global

The function of Global is to define global variables, but this global variable does not apply to the entire website, but to the current page, including all files in include or require.

However, global variables defined within the function body can be used within the function body, while global variables defined outside the function body cannot be used within the function body. See the example below for details.

(1) Define global variables within the function body, which can be used within the function body.

(2) Define global variables outside the function body and cannot use them inside the function body.

2.$GLOBALS

In the $GLOBALS array, each variable is an element, the key name corresponds to the variable name, and the value corresponds to the variable's content . $GLOBALS exists in the global scope because $GLOBALS is a superglobal variable. Pay attention to the writing method of $GLOBALS. For example, the variable $a1 is written as $GLOBALS['a1'].

Example: First use global definition

Use $GLOBALS to define global variables

eg: global

function test() { global $a;//定义全局变量a unset($a); //删除变量a //print $a;//会报错，因为unset已经把$a删除了。 } $a = 2; //定义一个变量atest(); //调用test()方法print $a; //输出a，输出的其实是$a = 2,所以结果为2.

eg: $GLOBALS

function test_global() { global $var1, $var2; $var2 =& $var1; } function test_globals() { $GLOBALS['var3'] =& $GLOBALS['var1']; } $var1 = 5; $var2 = $var3 = 0; test_global(); print $var2; //输出结果为0test_globals(); print $var3; //输结果为5

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