PHP website development variable scope _ PHP Tutorial

Variable scope in PHP website development. 1. PHP has no global static variables. NET was previously developed. you can use the following method to cache some data: viewplaincopytoclipboardprint? PublicclassTest {private 1. there is no global static variable in PHP.

In previous. NET development, you can use the following method to cache some data:

View plaincopy to clipboardprint? Public class Test { Private static int Count = 0; // This variable is valid throughout the application. } Public class Test { Private static int Count = 0; // This variable is valid throughout the application. }

PGP is an interpreted language. although there is a static modifier, the meaning is completely different from that in. NET.

Even if you declare a variable in the class as static, this variable is only valid in the current page-level application domain.

2. understand the scope of variables

Variables declared in vitro of the method cannot be accessed in the method body.

For example:

view plaincopy to clipboardprint? $url = "www.51cto.com"; function _DisplayUrl() { echo $url; } function DisplayUrl() { global $url; echo $url; } _DisplayUrl(); DisplayUrl(); ?> $url = "www.51cto.com"; function _DisplayUrl() { echo $url; } function DisplayUrl(){ global $url; echo $url; } _DisplayUrl(); DisplayUrl(); ?>

The _ DisplayUrl method does not display any results, because the variable $ url cannot be accessed in the method body _ DisplayUrl. you can add global before $ url, such as the DisplayUrl method.

Global variables defined in the method body can be accessed in the method body in vitro:

view plaincopy to clipboardprint? 　 function _DisplayUrl() { global $myName; $myName='yibin'; } _DisplayUrl(); echo $myName; //output yibin ?>

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In the previous. NET development of idea, you can use the following method to cache some data: view plaincopy to clipboardprint? Public class Test {private...