在 PHP 中使用 settype 而不是使用括号进行类型转换,有什么区别?

2022-01-13 00:00:00 type-conversion casting php

在 PHP 中,您可以将某些东西类型转换为这样的对象;(object) 或者您可以使用 settype($var, "object") - 但我的问题是两者之间有什么区别?

In PHP you can typecast something as an object like this; (object) or you can use settype($var, "object") - but my question is what is the difference between the two?

哪一个更有效/更好用?目前我发现 using (object) 可以完成这项工作,但想知道为什么还有一个 settype 函数.

Which one is more efficient / better to use? At the moment I find using (object) does the job, but wondering why there is a settype function as well.

推荐答案

强制转换改变了变量在当前上下文中被视为什么,settype 永久改变它.

Casting changes what the variable is being treated as in the current context, settype changes it permanently.

$value = "100"; //Value is a string
echo 5 + (int)$value; //Value is treated like an integer for this line
settype($value,'int'); //Value is now an integer

基本上 settype 是一个快捷方式:

Basically settype is a shortcut for:

$value = (type)$value;

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