Python C扩展：从引擎中提取参数 [英] Python C extension: Extract parameter from the engine

问题描述

我想使用Python对我的函数执行数学测试。可以访问Python的典型程序是：

I would like to use Python to perform Mathematics tests on my functions. A typical program that can gain access to Python is this:

#include <iostream>
#include <string>
#include <Python.h>
int RunTests()
{
    Py_Initialize();

    PyRun_SimpleString("a=5");
    PyRun_SimpleString("b='Hello'");
    PyRun_SimpleString("c=1+2j");
    PyRun_SimpleString("d=[1,3,5,7,9]");

    //question here

    Py_Finalize();
    return 0;
}

我的问题是：如何提取参数 a，b，c，d 到 PyObject s？

My question is: How can I extract the parameters a,b,c,d to PyObjects?

推荐答案

PyRun_SimpleString（）在 __ main __ 模块的上下文中执行代码。您可以使用 PyImport_AddModule（）检索此模块的引用，从此模块获取全局字典并查找变量：

PyRun_SimpleString() executes the code in the context of the __main__ module. You can retrieve a reference to this module using PyImport_AddModule(), get the globals dictionary from this module and lookup variables:

PyObject *main = PyImport_AddModule("__main__");
PyObject *globals = PyModule_GetDict(main);
PyObject *a = PyDict_GetItemString(globals, "a");

而不是使用这种方法，你最好创建一个新的 c>全局字符 c> c：> c> 字典并使用 PyRun_String

Instead of using this approach, you might be better off creating a new globals dictionary and using PyRun_String() to execute code in the context of that globals dict:

PyObject *globals = PyDict_New();
PyObject *a = PyRun_String("5", Py_single_input, globals, globals);

这样，您不需要先将表达式的结果存储在某个变量中，然后从 __ main __ 的全局范围中提取它。您仍然可以使用变量来存储中间结果，然后可以从上面的全局变量中提取。

This way, you don't need to first store the result of your expression in some variable and then extract it from the global scope of __main__. You can still use variables to store intermediate results, which can then be extracted from globals as above.

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