php - 为什么我会收到 "Only variables should be passed by reference"错误？

Question

检查这段代码:

$last = end($p = explode('/', $someString));  

收到此通知:

Only variables should be passed by reference

我真的很困惑，因为 $p 是一个变量。

Answer 1

end() 需要一个变量，而不是一个引用。在你的例子中 $p = explode('/', $someString) 不是一个变量，它是一个赋值。作为documentation说:

This array is passed by reference because it is modified by the function. This means you must pass it a real variable and not a function returning an array because only actual variables may be passed by reference.

你应该这样做:

$p = explode('/', $someString);
$last = end($p);