Cython:将内存视图转换为NumPy数组 [英] Cython: Convert memory view to NumPy array

问题描述

如何在cython中将类型化的memoryview转换为NumPy数组?文档有

How to convert a typed memoryview to an NumPy array in cython? The docs have

cimport numpy as np
import numpy as np

numpy_array = np.asarray(<np.int32_t[:10, :10]> my_pointer)

我为我的案件接受了

np.asarray(<np.float_t[:, :]> my_memview)

使用此编译器会告诉我:

Using this the compiler tells me:

Can only create cython.array from pointer or array

复制与否不是决定性的.我对此没有任何帮助.

Copying or not is not so decicive. I couldn't find any help on this.

推荐答案

您应该只能够直接在memoryview本身上使用np.asarray，所以类似:

You should just be able to use np.asarray directly on the memoryview itself, so something like:

np.asarray(my_memview)

应该工作.例如，如果您的cython源文件包含以下内容:

should work. For example if your cython source file contains this:

import numpy as np
cimport numpy as np
def test(double[:,:] x):
    print type(x)
    print type(np.asarray(x))

然后在编译它之后，您应该能够从python方面执行以下操作:

Then after compiling it, you should be able to do the following from the python side:

a = np.random.normal(size=(5,5))
test(a)

将产生以下输出:

<type '_cython_magic_0182fca918bfa3618c3553e51b13e8ba._memoryviewslice'>
<type 'numpy.ndarray'>

注意:我正在为IPython使用cythonmagic扩展.

Note: I'm using the cythonmagic extension for IPython.

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