如何执行python程序并使用exec()获取变量? [英] How to execute Python program and get the variables using exec()?

问题描述

我想使用exec()执行正确的Python程序，然后在执行后获取变量及其值. Google说我应该创建一个字典，然后在其中写入执行结果:exec(code_object)在变量中.但不幸的是，Python 3中没有.

I want to execute a correct Python program using exec() and then get variables and their values after executing. Google says that I should create a dictionary and write the result of execution there: exec(code_object) in variables. But unfortunately that doesn't in Python 3.

推荐答案

Python 3中的代码应为:

The code in Python 3 should be:

exec(code_object, variables)

此语法也是 Python 2兼容.

exec(code_object) in variables

可以编译并在Python 3中运行，但做一些与Python 2完全不同的事情-它会在当前范围内执行code_object； exec将返回None;然后，由于None不是variables中的键，因此表达式None in variables将对False求值；结果将被删除-因此，除了code_object看到错误的作用域之外，不会发生编译时或运行时错误.

would compile and run in Python 3 but do something completely different from Python 2 - it would execute the code_object in current scope; the exec would return None; then the expression None in variables would evaluate False since None is not a key in variables; the result would be dropped - thus neither compile time nor possibly run-time error occurs, except for code_object seeing the wrong scope.

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