如何获取字符串中给定名称的变量的值? [英] How to get the value of a variable given its name in a string?

问题描述

为简单起见，这是我想要做的精简版:

def foo(a):# 我想打印变量的值# 其名称包含在一个

我知道如何在 PHP 中执行此操作:

function foo($a) {回声 $$a;}全局 $string = "blah";//可能不需要是全局的，但这无关紧要foo("字符串");//打印等等"

有没有办法做到这一点?

解决方案

如果是全局变量，那么你可以这样做:

<预><代码>>>>一 = 5>>>全局变量()['a']5

关于各种eval"解决方案的注意事项:您应该小心使用 eval，尤其是如果您正在评估的字符串来自可能不受信任的来源——否则，您最终可能会删除磁盘的全部内容或如果您收到恶意字符串，则类似这样的事情.

(如果它不是全局的，那么你需要访问它定义的任何命名空间.如果你没有它，你将无法访问它.)

For simplicity this is a stripped down version of what I want to do:

def foo(a):
    # I want to print the value of the variable
    # the name of which is contained in a

I know how to do this in PHP:

function foo($a) {
    echo $$a;
}

global $string = "blah"; // might not need to be global but that's irrelevant
foo("string"); // prints "blah"

Any way to do this?

解决方案

If it's a global variable, then you can do:

>>> a = 5
>>> globals()['a']
5

A note about the various "eval" solutions: you should be careful with eval, especially if the string you're evaluating comes from a potentially untrusted source -- otherwise, you might end up deleting the entire contents of your disk or something like that if you're given a malicious string.

(If it's not global, then you'll need access to whatever namespace it's defined in. If you don't have that, there's no way you'll be able to access it.)

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