如何通过另一个文件中另一个文件定义的变量来使用该文件中包含eval的函数? [英] How to use a function containing eval in a file by variable defined at another file from that another file?

问题描述

假设，我创建了一个python文件(FirstFile.py)名称，其中包含许多功能和其他内容.功能之一就是这个(当然，它是简化的):

Assume, I have created an python file (FirstFile.py) name which contains many functions and other things. One of the function is this (of course, it is simplified):

def func(string):
    assert eval(string)

此外，我还创建了一个python文件，该文件从上述文件中导入func().然后，第二个python文件尝试执行以下过程:

Besides, I have created an python file which imports func() from the file mentioned above. Then this second python file try to execute following process:

from FirstFile import func
amk = 1
func("amk == 1")

当变量"amk"在第一个文件中时，没有任何问题.但是，当变量"amk"在第二个文件中时(如此处所示)，将显示错误:

When variable "amk" is in the first file, no problem reveals. However, when variable "amk" is in the second file, which is illustrated here, an error reveals:

NameError: name 'amk' is not defined 

您想请帮我解决这个问题吗?

Would you like to please help me solve this problem?

推荐答案

默认情况下，eval在当前的本地/全局范围内执行，如果要指定其他环境，则可以执行以下操作:

by default eval executes in the current local/global scope, if you want to specify a different environment you can do something like:

eval("x == 1", {"x":1})

因此您的函数可以使用可选的environ参数:

so your function could take an optional environ argument:

def func(string, environ=None):
    assert eval(string, environ)

然后您可以从另一个以locals()为环境的模块中调用该函数:

then you can call the function from the other module passing locals() as the environment:

from FirstFile import func
amk = 1
func("amk == 1", locals())

作为旁注，我建议不要评估任意代码，尤其是当它来自另一个源/模块时，因为它可能偶然包含有害代码.

As a side note I'd recommend against evaluating arbitrary code especially if it is coming from another source / module as it could accidentally contain harmful code.

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