ctypes-numpy数组没有形状?
我正在使用python包装器来调用c ++ dll库的函数. dll库返回一个ctype,我将其转换为numpy数组
I am using a python wrapper to call functions of a c++ dll library. A ctype is returned by the dll library, which I convert to numpy array
score = np.ctypeslib.as_array(score,1)
但是,数组没有形状吗?
however, the array has no shape?
score
>>> array(-0.019486344729027664)
score.shape
>>> ()
score[0]
>>> IndexError: too many indices for array
如何从分数数组中提取双精度数?
How can I extract a double from the score array?
谢谢.
您可以通过索引[()]
来访问0维数组内的数据.
You can access the data inside a 0-dimensional array via indexing [()]
.
例如,score[()]
将检索数组中的基础数据.
For example, score[()]
will retrieve the underlying data in your array.
这个习惯用法实际上是一致的:
The idiom is in fact consistent:
# x, y, z are 0-dim, 1-dim, 2-dim respectively
x = np.array(1)
y = np.array([1, 2, 3])
z = np.array([[1, 2, 3], [4, 5, 6]])
# use 0-dim, 1-dim, 2-dim tuple indexers respectively
res_x = x[()] # 1
res_y = y[(1,)] # 2
res_z = z[(1, 2)] # 6
音色看起来不自然,因为您无需在1d和2d情况下显式使用它们,即y[1]
和z[1, 2]
就足够了.该选项不适用于0-dim情况,因此请使用零长度元组.
Tuples seem unnatural because you don't need to use them explicitly for the 1d and 2d cases, i.e. y[1]
and z[1, 2]
suffice. That option isn't available for the 0-dim case, so use the zero-length tuple.