如何访问以数字开头的对象属性? [英] How can I access an object attribute that starts with a number?

问题描述

我正在使用现有的代码库，并返回了一个对象，该对象的属性以数字开头，可以看到是否在该对象上调用了print_r.

I'm working on an existing code base and got back an object with an attribute that starts with a number, which I can see if I call print_r on the object.

假设它是$Beeblebrox->2ndhead.当我尝试像这样访问它时，出现错误:

Let's say it's $Beeblebrox->2ndhead. When I try to access it like that, I get an error:

解析错误:语法错误，意外的T_LNUMBER，预期为T_STRING或T_VARIABLE或'{'或'$'

Parse error: syntax error, unexpected T_LNUMBER, expecting T_STRING or T_VARIABLE or '{' or '$'

如何获取该属性?

推荐答案

这是怎么回事:

$Beeblebrox->{'2ndhead'}

实际上，您几乎可以对任何种类的变量执行此操作，即使不是类属性的变量也是如此.

Actually, you can do this for pretty much any kind of variable -- even for ones that are not class properties.

例如，您可以考虑一个包含空格的变量名称；以下语法将起作用:

For example, you could think about a variable's name that contains spaces ; the following syntax will work :

${"My test var"} = 10;
echo ${"My test var"};

即使，显然，您将无法执行以下操作:

Even if, obviously, you would not be able to do anything like this :

$My test var = 10;
echo $My test var;

不过，不知道它在内部如何工作.经过一番搜索，我在PHP手册中找不到任何有关此的信息.

No idea how it's working internally, though... And after a bit of searching, I cannot find anything about this in the PHP manual.

我只能在这里找到有关{}和变量的信息:

Only thing I can find about {} and variables is in here : Variable parsing -- but not quite related to the current subject...

但是这里的文章显示了其他两种可能性，并且比我在此处发布的示例更进一步: PHP变量名:Curly Brace Madness

But here's an article that shows a couple of other possiblities, and goes farther than the examples I posted here : PHP Variable Names: Curly Brace Madness

这是另一个提供有关解析方式的其他信息:

And here's another one that gives some additionnal informations about the way those are parsed : PHP grammar notes

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