如何使用C API创建datetime64对象的Numpy数组? [英] How to create of Numpy array of datetime64 objects using C API?

问题描述

我需要从C/C ++代码创建一个numpy datetime64对象数组.如您所见，对于NPY_LONGLONG和NPY_VOID，我做到了.对于NPY_DATETIME类型，我需要做同样的事情.

I need to create an array of numpy datetime64 objects from C/C++ code. As you can see for NPY_LONGLONG and NPY_VOID I did it. I need to do the same thing for NPY_DATETIME type.

PyObject *arr1 = PyArray_SimpleNew(1, &dims, NPY_LONGLONG);
PyObject *arr2 = PyArray_New(&PyArray_Type, 1, &dims, NPY_VOID, NULL, NULL, item_size, 0, NULL);

问题是没有关于NPY_DATETIME类型的内部表示形式的文档，所以我不知道它是否具有固定的大小，结构.

The problem is that there is no documentation about what is the internal representation of NPY_DATETIME type, so I don't know if it has an fixed size, structure or not.

如果您像我对NPY_LONGLONG和NPY_VOID所做的示例一样，那将很棒.

It would be great if you put an example like I did for NPY_LONGLONG and NPY_VOID.

推荐答案

我找到了一个很好的解决方案.这是我的函数，它从C缓冲区创建numpy数组.

I found a good solution. Here is my function that creates numpy array from a C buffer.

PyObject* create_datetime_array(int index, std::string const &dtype)
{
    int buffer_size = this->elements_count*sizeof(omd::OT_int64);
    npy_intp dims = this->elements_count;
    PyObject *date_type = Py_BuildValue("s", dtype.c_str());
    PyArray_Descr *descr;
    PyArray_DescrConverter(date_type, &descr);
    Py_XDECREF(date_type);
    PyObject *arr = PyArray_SimpleNewFromDescr(1, &dims, descr);
    memcpy(PyArray_BYTES((PyArrayObject *)arr), &(this->int64_data[index][0]), buffer_size);
    return arr;
}

dtype是M8 [ms]或M8 [us]或M8 [ns].

dtype is M8[ms] or M8[us] or M8[ns].

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