使用PHP 5.3?:运算符 [英] Using PHP 5.3 ?: operator

问题描述

使用此测试页:

$page   = (int) $_GET['page'] ?: '1';
echo $page;

当页面未定义时，我不明白我得到的输出:

I don't understand the output I'm getting when page is undefined:

Request   Result
?page=2   2
?page=3   3
?page=    1
?         error: Undefined index page

为什么出现错误信息?它是PHP 5.3；为什么不回显"1"?

Why the error message? It's PHP 5.3; why doesn't it echo "1"?

推荐答案

(在我看来)正确的方法是:

The proper way (in my opinion) would be:

$page = isset($_GET['page']) ? (int) $_GET['page'] : 1;

即使您使用了新样式，也会出现?page=0的问题(因为0的值为false). 新" 并不总是更好……您必须知道何时才能使用它.

Even if you used the new style, you would have problems with ?page=0 (as 0 evaluated to false). "New" is not always better... you have to know when to use it.

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